CBSE Class 11 Physics Work Energy And Power Worksheet

Read and download free pdf of CBSE Class 11 Physics Work Energy And Power Worksheet. Students and teachers of Class 11 Physics can get free printable Worksheets for Class 11 Physics Chapter 6 Work Energy and Power in PDF format prepared as per the latest syllabus and examination pattern in your schools. Class 11 students should practice questions and answers given here for Physics in Class 11 which will help them to improve your knowledge of all important chapters and its topics. Students should also download free pdf of Class 11 Physics Worksheets prepared by school teachers as per the latest NCERT, CBSE, KVS books and syllabus issued this academic year and solve important problems with solutions on daily basis to get more score in school exams and tests

Worksheet for Class 11 Physics Chapter 6 Work Energy and Power

Class 11 Physics students should refer to the following printable worksheet in Pdf for Chapter 6 Work Energy and Power in Class 11. This test paper with questions and answers for Class 11 will be very useful for exams and help you to score good marks

Class 11 Physics Worksheet for Chapter 6 Work Energy and Power

Work Energy and Power MCQ Questions with Answers Class 11 Physics Chapter 6

Question- A body is attached to the lower end of a vertical spiral spring and it is gradually lowered to its equilibrium position. This stretches the spring by a length d. If the same body attached to the same spring is allowed to fall suddenly, what would be the maximum stretching in this case ?
(a) d
(b) 2d
(c) 3d
(d)1/2 d
Ans-(b)
 
Question-  A coconut of mass 1.0 kg falls to earth from a height of 10 m. The kinetic energy of the coconut, when it is 4 m above ground is :
(a) 0.588 joule
(b) 58.8 joule
(c) 5.88 joule
(d) 588 joule
Ans-(b)
 
Question-  Calculate the K.E. and P.E. of the ball half way up, when a ball of mass 0.1 kg is thrown vertically upwards with an initial speed of 20 m/s–1.
(a) 10 J, 20 J
(b) 10 J, 10 J
(c) 15 J, 8 J
(d) 8 J, 16 J.
Ans-(b)
 
Question-  If a body of mass 3 kg is droped from top of a tower of height 250 m, then its kinetic energy after 3 sec. will be
(a) 1126 J
(b) 1048 J
(c) 735 J
(d) 1296.5 J
Ans-(d)
 
Question- A body of mass 2 kg moves down the quadrant of a circle of radius 4 m. The velocity on reaching the lowest point is 8 m/s.What is work done against friction ?
(a) 14.4 J
(b) 28.8 J
(c) 64 J
(d) Zero
Ans-(a)
 
Question-  The KE of a 500 gram stone is 100 J. Against a force of 50 N,how long will it travel ?
(a) 0.2 s
(b) 0.1 s
(c) 0.3 s
(d) 0.4 s
Ans-(a)
 
Question- If water falls from a dam into a turbine wheel 19.6 m below,then velocity of water at turbine, is (Take g = 9.8 m/s2)
(a) 9.8 m/s
(b) 19.6 m/s
(c) 39.2 m/s
(d) 98.0 m/s
Ans-(b)
 
Question-  The work done by pseudo forces is
(a) positive
(b) negative
(c) zero
(d) all of these
Ans-(d)
 
Question-  A uniform chain of length L and mass M is lying on a smooth table and one third of its length is hanging vertically down over the edge of the table. If g is acc. due to gravity, work required to pull the hanging part on to the table is
(a) MgL
(b) Mg L/3
(c) Mg L/9
(d) Mg L/18
Ans-(d)
 
Question-  An object moving horizontally with kinetic energy of 800 J experiences a constant opposing force of 100 N while moving from a to b (where ab = 2m). The energy of particle at b is :
(a) 700 J
(b) 400 J
(c) 600 J
(d) 300 J
Ans-(c)
 
Question-  A block of mass 0.5 kg has an initial velocity of 10 m/s. down an inclined plane of angle 30°, the coefficient of friction between the block and the inclined surface is 0.2. The velocity of the block after it travels a distance of 10 m is:
(a) 17 m/s
(b) 13 m/s
(c) 24 m/s
(d) 8 m/s
Ans-(b)
 
Question-  A body is falling with velocity 1 m/s at a height 3 m from the ground. The speed at height 2 m from the ground will be :
(a) 4.54 m/s
(b) 1 m/s
(c) 6 m/s
(d) 5.32 m/s
Ans-(a)
 
Question-  A pump of 200 W power is lifting 2 kg water from an average depth of 10 m per second. Velocity of water delivered by the pump is (g = 9.8 m/s2)
(a) 3 m/s
(b) 2 m/s
(c) 4 m/s
(d) 1 m/s
Ans-(b)
 
Question- A machine gun fires 360 bullets per minute, with a velocity of 600 m/s. If the power of the gun is 5.4 kW, mass of each bullet is
(a) 5 kg
(b) 0.5 kg
(c) 5 g
(d) 0.5 g
Ans-(c)
 
Question-  A train of mass 100 ton is moving up an incline of 1 in 100 at a constant speed of 36 km ph. If the friction per ton is 100 N,then power of the engine is
(a) 198 kW
(b) 96 kW
(c) 298 kW
(d) 398 kW
Ans-(a)
 
Question- The power of a water pump is 2 kW. If g = 10 m/s2, the amount of water is can raise in one minute to a height of 10 m is
(a) 2000 litre
(b) 1000 litre
(c) 100 litre
(d) 1200 litre
Ans-(d)
 
Question-  A man is riding on a cycle with velocity 7.2 km/hr up a hill having a slope 1 in 20. Total mass of the man and cycle is 100 kg. The power of man is :
(a) 98 W
(b) 49 W
(c) 196 W
(d) 147 W
Ans-(a)
 
Question-  Power applied to a particle varies with time as P = (3t2 – 2t + 1)W,where t is in second. Find the change in its kinetic energy between time t = 2s and t = 4s.
(a) 32 J
(b) 46 J
(c) 61 J
(d) 102 J
Ans-(b)
 
Question- . A spring of force constant 800 N/m has an extension of 5 cm. The work done in extending it from 5 cm to 15 cm is
(a) 16 J
(b) 8 J
(c) 32 J
(d) 24 J
Ans-(b)
 
Question-  A spring of spring constant 5 × 103 N/m is stretched initially by 5 cm from the unstreched position. Then the work required to stretch it further by another 5 cm is 
(a) 12.50 N-m
(b) 18.75 N-m
(c) 25.00 N-m
(d) 6.25N-m
Ans- (b)
 
Question-  A body is moved along a straight line by a machine delivering a constant power. The distance moved by the body in time t is proportional to 
(a) t3/4
(b) t3/2
(c) t1/4
(d) t1/2
Ans- (b)
 
Question- A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to (2004)
(a) x2
(b) ex
(c) x
(d) loge x
Ans- (a)
 
Question- A bullet fired into a fixed target loses half of its velocity after penetrating 3 cm. How much further it will penetrate before coming to rest, assuming that it faces constant resistance to motion ? 
(a) 3.0 cm
(b) 2.0 cm
(c) 1.5 cm
(d) 1.0 cm
Ans-(d)
 
Question-  A bomb of mass 16 kg at rest explodes into two pieces of masses 4 kg and 12 kg. The velocity of the 12 kg mass is 4 ms–1. The kinetic energy of the other mass is 
(a) 144 J
(b) 288 J
(c) 192 J
(d) 96 J
Ans- (b)
 
Question- A time dependent force F = 6t acts on a particle of mass 1 kg. If the particle starts from rest, the work done by the force during the first 1 second will be : 
(a) 4.5 J
(b) 22 J
(c) 9 J
(d) 18 J
Ans- (a)

Question- A body of mass m = 10–2 kg is moving in a medium and experiences a frictional force F = –kv2. Its initial speed is v0 = 10 ms–1. If, after 10s, its energy is  1/8 mv02 , the value of k will be : 

(a) 10–1 kg m–1 s–1
(b) 10–3 kg m–1
(c) 10–3 kg s–1
(d) 10–4 kg m–1
Ans-(d)
 
Question- A spring of unstretched length l has a mass m with one end fixed to a rigid support. Assuming spring to be made of a uniform wire, the kinetic energy possessed by it if its free end is pulled with uniform velocity v is:
(a) 1/3 mv
(b) 1/6 mv 2 
(c) 1/2  mv 2 
(d) m mv 2 
Ans-(a)
 
Question- A car of weight W is on an inclined road that rises by 100 m over a distance of 1 km and applies a constant frictional force W/20 on the car. While moving uphill on the road at a speed of 10 ms–1, the car needs power P. If it needs power P/2 while moving downhill at speed v then value of v is :
(a) 20 ms–1
(b) 15 ms–1
(c) 10 ms–1
(d) 5 ms–1
Ans-(a)
 
Question-A small block of mass m is kept on a rough inclined surface of inclination θ fixed in an elevator. The elevator goes up with a uniform velocity v and the block does not slide on the wedge. The work done by the force of friction on the block in a time t will be :
(a) Zero
(b) mgvt cos2 θ
(c) mgvt sin2θ
(d)1/2 mgvt sin2θ
Ans- (c)
 
Question- Work done by a conservative force on a system is equal to
(a) the change in kinetic energy of the system
(b) the change in potential energy of the system
(c) the change in total mechanical energy of the system
(d) none of the above
Ans- (d)
 
Question- A ball is released from the top of a tower. The ratio of work done by force of gravity in first, second and third second of the motion of ball is
(a) 1 : 2 : 3
(b) 1 : 4 : 16
(c) 1 : 3 : 5
(d) 1 : 9 : 25
Ans-(c) 
 
Question-A man throws the bricks to a height of 12 m where they reach with a speed of 12 m/s. If he throws the bricks such that they just reach that height, what percentage of energy will be saved (g = 9.8 m/s2)
(a) 29%
(b) 46%
(c) 38%
(d) 50%
Ans-(c)
 
Question- A man raises 1 kg wt. to a height of 100 cm and holds it there for 30 minutes. How much work has he performed ?
(a) 1 × 9.8 J
(b) 1 × 9.8 × 30 × 60 J
(c) 1 × 9.8 × 30 J
(d) 1 × 9.8 × 30 erg.
Ans-(a) 
 
Question- A ball is dropped a height of 20 cm. Ball rebounds to a height of 10 cm. What is the loss of energy ?
(a) 25%
(b) 75%
(c) 50%
(d) 100%
Ans-(c) 
 
Question- A machine, which is 75% efficient, uses 12 J of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. the velocity at the end of its fall is (in ms–1)
(a) √24
(b) √32
(c) √18
(d) √9
Ans-(c) 
 
Question- A rope ladder with a length l carrying a man with a mass m at its end is attached to the basket of balloon with a mass M. The entire system is in equilibrium in the air. As the man climbs up the ladder into the balloon, the balloon descends by a height h. Then the potential energy of the man
(a) increases by mg (l – h)
(b) increases by mgl
(c) increase by mgh
(d) increases by mg (2l – h)
Ans-(a) 
 
Question- A particle moves in a straight line with retardation proportional to its displacement. Its loss of KE for any displacement x is proportional to
(a) x
(b) x2
(c) x0
(d) ex
 Ans-(b)
 
Question-An engine pumps water continuously through a hole. Speed with which water passes through the hole nozzle is v and k is the mass per unit length of the water jet as it leaves the nozzle. Find the rate at which kinetic energy is being imparted to the water.
(a)1/2 kv2
(b) 1/2kv3
(c)v2/2k
(d)v 32k
Ans-(b)
 
Question- A uniform flexible chain of mass m and length 2l hangs in equilibrium over a smooth horizontal pin of negligibile diameter. One end of the chain is given a small vertical displacement so that the chain slips over the pin. The speed of chain when it leaves pin is :
(a) √2gl
(b)√gl
(c) √4gl
(d) √3gl
Ans-(b)
 
Question- A meter stick of mass 400 g is pivoted at one end and displaced through an angle 60°. The increase in its potential energy is :
(a) 1 J
(b) 10 J
(c) 100 J
(d) 1000 J
Ans-(a)
 
Question- Power supplied to a particle of mass 2 Kg varies with time as P = 3t2/2 watt, here t is in second. If velocity of particle at t = 0 is v = 0. The velocity of particle at time t = 2 s will be
(a) 1 m/s
(b) 4 m/s
(c) 2 m/s
(d) 2 √2 m/s
Ans-(c)
 
Question- A dam is situated at a height of 550 m above sea level and supplies water to a power house which is at a height of 50m above see level. 2000 kg of water passes through the turbines per second. What would be the maximum electricl power output of the power house if the whole system were 80% efficient ?
(a) 8 MW
(b) 10 MW
(c) 12.5 MV
(d) 16 MV
Ans-(a)
 
Question- A 500 kg car, moving with a velocity of 36 km h–1 on a straight raod unidirectionally, doubles its velocity in one minute.The power delivered by the engine for doubling the velocity is
(a) 750 W
(b) 1050 W
(c) 1150 W
(d) 1250 W
Ans-(d)
 
Question- The power of a water jet flowing through an orifice of radius r with velocity v is
(a) zero
(b) 500 Πr2v2
(c) 500 Πr2v3
(d) Πr4v
Ans-(c)
 
Question- A pendulum of mass 1 kg and length θ = 1 m is released from rest at angle θ  = 60°. The power delivered by all the forces acting on the bob at angle θ  = 30° will be : (g = 10 m/s2)
(a) 13.5 W
(b) 20.4 W
(c) 24.6 W
(d) zero
Ans-(a)
 
Question- The potential energy of a particle of mass 1 kg is, U = 10 + (x – 2)2.Here, U is in joules and x in metres on the positive x-axis.Particle travels upto x = +6 m. Choose the correct statement:
(a) On negative x-axis particle travels upto x = – 2m
(b) The maximum kinetic energy of the particle is 16 J
(c) Both (a) and (b) are correct
(d) Both (a) and (b) are wrong
Ans-(c)

Question-  The extra force required to keep the belt moving is

(a) 0.4 N
(b) 0.08 N
(c) 0.04 N
(d) 0.2 N
Ans-(a)
 
Question- The extra power required is
(a) 0.4 W
(b) 0.08 W
(c) 0.04 W
(d) 0.2 W
Ans-(b)
 
Question-  The time rate of change of kinetic energy of sand particles is
(a) 0.4 J/s
(b) 0.08 J/s
(c) 0.04 J/s
(d) 0.2 J/s
Ans-(c)
 
Question-  If the total mechanical energy of the particle is –40 J, then it can be found in region
(a) x < – 10 and x > 15
(b) –10 < x < –5 and 6 < x < 15
(c) 10 < x < 15
(d) it is not possible.
Ans-(d)
 
Question- If the particle is isolated and its total mechanical energy is 60 J, then
(a) the particle can be found anywhere from – ∞ < x < ∞
(b) the particle’s maximum kinetic energy is 95 J.
(c) the particle’s kinetic energy is not getting zero anywhere on x-axis
(d) all of the above.
Ans-(d)
 
Question-  Assertion : Stopping distance = Kinetic energy/Stopping force .
Reason : work done in stopping a body is equal to KE of the body.
(a) A
(b) B
(c) C
(d) D
Ans-(a)
 
Question- Assertion : A weight lifter does not work in holding the weight up.
Reason : Work done is zero because distance moved is zero.
(a) A
(b) B
(c) C
(d) D
Ans-(a)
 
Question-  Assertion : Mass and energy are not conserved separately,but are conserved as a single entirly ‘mass-energy’.
Reason : This is because one can be obtained at the cost of the other as per Einstein equaiton.E = mc2
 
(a) A
(b) B
(c) C
(d) D
Ans-(a)
 
Question-  Assertion : In a circular motion, work done by centripetal force is not zero always.
Reason : If speed of the particle increases or decreases in circular motion, net force acting on the particle does not remain towards centre.
(a) A
(b) B
(c) C
(d) D
Ans-(d)
 
Question- Assertion : A body is connected to a string and if it just completes a circle, it must have zero velocity at the top.
Reason : A body is projected in vertically upward direction,at the highest point the acceleration of the particle is nonzero.
(a) A
(b) B
(c) C
(d) D
Ans-(d)
 
Question- Assertion : Under the action of a force of constant magnitude, work done is path independent.
Reason : Work done by force of gravity is path independent only near the surface of Earth.
(a) A
(b) B
(c) C
(d) D
Ans-(d)
 
Question-  A spring of force-constant k is cut into two pieces such that one piece is double the length of the other. Then the long piece will have a force-constant of : 
(a) (2/3)k
(b) (3/2)k
(c) 3 k
(d) 6 k
Ans-(b)
 
Question- A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A plump bob is suspended from the roof of the car by a light rigid rod. The angle made by the rod with the track is (g = 10 m/s2
(a) zero
(b) 30°
(c) 45°
(d) 60°
Ans-(c)
 
Question- Unit of energy is
(a) kwh
(b) joule
(c) electron volt
(d) All of these

Answer: D

Question- The magnitude of work done by a force
(a) depends on frame of reference
(b) does not depend on frame of reference
(c) cannot be calculated in non-inertial frames.
(d) both (a) and (b)

Answer: A

Question- Kinetic energy, with any reference, must be
(a) zero
(b) positive
(c) negative
(d) both (b) and (c)

Answer: B

Question- A boy carrying a box on his head is walking on a level road from one place to another is doing no work. This statement is
(a) correct
(b) incorrect
(c) partly correct
(d) cannot say

Answer: A

Question-In which of the following work is being not done?
(a) Shopping in the supermarket
(b) Standing with a basket of fruit on the head
(c) Climbing a tree
(d) Pushing a wheel barrow

Answer: B

Question-If a light body and heavy body have same kinetic energy,then which one has greater linear momentum?
(a) Lighter body
(b) Heavier body
(c) Both have same momentum
(d) Can’t be predicted

Answer: B

Question-A man pushes a wall and fails to displace it, he does
(a) negative work
(b) positive but not maximum work
(c) no work at all
(d) maximum positive work

Answer: C

Question-According to work-energy theorem, the work done by the net force on a particle is equal to the change in its
(a) kinetic energy
(b) potential energy
(c) linear momentum
(d) angular momentum

Answer: A

Question-Work is always done on a body when
(a) a force acts on it
(b) it moves through a certain distance
(c) it experiences an increase in energy through a mechanical influence
(d) None of these

Answer: C

Question-Total ....X.... energy of a system is conserved, if the forces, doing work on it, are .....Y..... .Here, X and Y refer to
(a) conservative, mechanical
(b) mechanical, conservative
(c) mechanical, non-conservative
(d) kinetic, conservative

Answer: B

Question-No work is done if
(a) displacement is zero
(b) force is zero
(c) force and displacement are mutually perpendicular
(d) All of these

Answer: D

Question- A bullet is fired and gets embedded in block kept on table. If table is frictionless, then
(a) kinetic energy gets conserved
(b) potential energy gets conserved
(c) momentum gets conserved
(d) both (a) and (c)

Answer: C

Question- Which of the following is not a conservative force?
(a) Gravitational force
(b) Frictional force
(c) Spring force
(d) None of these

Answer: B

Question-A light and a heavy body have equal momentum. Which one has greater K.E.?
(a) The lighter body
(b) The heavier body
(c) Both have equal K.E.
(d) Data given is incomplete

Answer: A

Question-When the force retards the motion of body, the work done is
(a) zero
(b) negative
(c) positive
(d) Positive or negative depending upon the magnitude of force and displacement

Answer: B

Question. A particle moves in the X–Y plane under the influence of a force F̅ such that its instantaneous momentum is p̅ = î2cost+ĵ2sint. What is the angle between the force and instantaneous momentum ?
(a) 0°
(b) 45°
(c) 90°
(d) 180°

Answer: C

Question. The bob A of a simple pendulum is released when the string makes an angle of 45º with the vertical. It hits another bob B of the same material and same mass kept at rest on the table. If the collision is elastic 
(a) both A and B rise to the same height
(b) both A and B come to rest at B
(c) both A and B move with the velocity of A
(d) A comes to rest and B moves with the velocity of A

Answer: D

Question. A body projected vertically from the earth reaches a height equal to earth's radius before returning to the earth. The power exerted by the gravitational force is greatest
(a) at the highest position of the body
(b) at the instant just before the body hits the earth
(c) it remains constant all through
(d) at the instant just after the body is projected

Answer: B

Question. A body is moving unidirectionally under the influence of a source of constant power supplying energy. Which of the diagrams shown in figure correctly shown the displacementtime curve for its motion? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-d

Answer: B

Question. A particle of mass m1moving with velocity v strikes with a mass m2 at rest, then the condition for maximum transfer of kinetic energy is
(a) m1 >> m2
(b) m2 >> m2
(c) m1 = m2
(d) m1 = 2m2

Answer: C

Question. Two blocks of masses 10 kg and 4 kg are connected by a spring of negligible mass and placed on a frictionless horizontal surface. An impulse gives a velocity of 14 m/s to the heavier block in the direction of the lighter block. The velocity of the centre of mass is
(a) 30 m/s
(b) 20 m/s
(c) 10 m/s
(d) 5 m/s

Answer: C

Question. A mass m is moving with velocity v collides inelastically with a bob of simple pendulum of mass m and gets embedded into it. The total height to which the masses will rise after collision is
(a) v2/8g
(b) v2/4g
(c) v2/2g
(d) 2v2/g

Answer: A

Question. A motor drives a body along a straight line with a constant force. The power P developed by the motor must vary with time t according to 
cbse-class-11-physics-work-energy-and-power-worksheet-set-d

Answer: D

Question. A glass marble dropped from a certain height above the horizontal surface reaches the surface in time t and then continues to bounce up and down. The time in which the marble finally comes to rest is
(a) en t
(b) e2t
(c) t[1+e/1-e]
(d) t[1-e/1+e]

Answer: C

Question. A weight suspended from the free end of a vertically hanging spring produces an extension of 3 cm. The spring is cut into two parts so that the length of the longer part is 2/3 of the original length, If the same weight is now suspended from the longer part of the spring, the extension produced will be
(a) 0.1 cm
(b) 0.5 cm
(c) 1 cm
(d) 2 cm

Answer: D

Question. A particle, initially at rest on a frictionless horizontal surface, is acted upon by a horizontal force which is constant in magnitude and direction. A graph is plotted of the work done on the particle W, against the speed of the particle v.
If there are no other horizontal forces acting on the particle, the graph would look like 
cbse-class-11-physics-work-energy-and-power-worksheet-set-d

Answer: C

Question. A particle of mass m moving eastward with a speed v collides with another particle of the same mass moving northwards with the same speed. If two particles coalesce on collision, the new particle of mass 2 m will move in the north-east direction with a velocity
(a) v / 2
(b) v √2
(c) v/ 2
(d) None of these

Answer: C

Question. A small block of mass m is kept on a rough inclined surface of inclination θ fixed in an elevator. The elevator goes up with a uniform velocity v and the block does not slide on the wedge. The work done by the force of friction on the block in time t as seen by the observer on the inclined p lane will be
(a) zero
(b) mgvt cos2θ
(c) mgvt sin2 θ
(d) mgvt sin2θ

Answer: A

Question. A ramp is constructed in parabolic shape such that the height y of any point on its surface is given in terms of the point's horizontal distance x from the bottom of the ramp be y = x2/2L. A block of granite is to be set on the ramp; the coefficient of static friction is 0.80. What is the maximum x coordinate at which the block can be placed on the ramp and remain at rest, if L = 10 m? 
(a) 8 m
(b) 8.4 m
(c) 9 m
(d) 9.4 m

Answer: A

Question. The force F acting on a body moving in a circle of radius r is always perpendicular to the instantaneous velocity v. The work done by the force on the body in half rotation is
(a) Fv
(b) F·2pr
(c) Fr
(d) 0

Answer: D

Question. The negative of the distance rate of change of potential energy is equal to
(a) force acting on the particle in the direction of displacement
(b) acceleration of the particle, perpendicular to displacement
(c) power
(d) impulse.

Answer: A

Question. n small balls each of mass m impinge elastically each second on a surface with velocity v. The force experienced by the surface will be
(a) 1/2 mnv
(b) 2 mnv
(c) mnv
(d) 2 mnv

Answer: C

Question. A horse drinks water from a cubical container of side 1 m. The level of the stomach of horse is at 2 m from the ground. Assume that all the water drunk by the horse is at a level of 2m from the ground. Then minimum work done by the horse in drinking the entire water of the container is (Take ρwater = 1000 kg/m3 and g = 10 m/s2 )
(a) 10 kJ
(b) 15 kJ
(c) 20 kJ
(d) zero

Answer: D

Question. A mass m moving horizontally (along the x-axis) with velocity v collides and sticks to mass of 3m moving vertically upward (along the y-axis) with velocity 2v. The final velocity of the combination is 
cbse-class-11-physics-work-energy-and-power-worksheet-set-d

Answer: A

Question. A body falls freely under gravity. Its velocity is v when it has lost potential energy equal to U. What is the mass of the body ?
(a) U2/v2
(b) 2U2/v2
(c) 2U/v2
(d) U /v2

Answer: C

 

Work and Energy - Work
 
Work done by force acting on an object is equal to the magnitude of the force multiplied by the displacement of the object in the direction of the force.
 
Condition for work to be done:
 A net force act on an object.
 The object must be displaced in the direction of the net force.
Definition of work: Work is said to be done when an object is displaced on applying a certain force.
Work done is the product of force and displacement: (W = F x s)
Work is measured in joule in the SI system. One (j) is the work done when the net force of one newton acts on body and displaces in the direction of the force by the metre.
Work in the CGS system is measured on erg. One is the work done when the net force of one dyne acts on a body and displaces it in the direction of the force by one centimetre.
The work done on the object is independent of the path transverse by the object.
Work done is a scalar.
Work done can be either positive or negative:
 Work done is positive if the force applied and the displacement, both are in the same direction.
 Work done is negative when the force acts in a direction opposite to the direction of displacement.
 
Work and Energy - Energy
Energy is defined as the capacity to do work.
The various forms of energy include kinetic energy, potential energy, light energy, thermal or heat energy, electrical energy and chemical energy.
Energy stored in an object due to its position or place is known as potential energy.
The gravitational potential energy of an object is the work done in raising it from the ground to a certain point against gravity. it is calculated using the expression PE=mgh.
The energy possessed in a moving object is called kinetic energy. it is calculated by the formula:
EK= ½ mv2
Where,
m is the mass of the object
v is the velocity of the object
Energy can be converted from one form to another.
Law of conservation of energy: energy can neither be created nor destroyed, but can change its form.
Power (P) is the rate of doing work.
It is calculated using the expression:
P = W/t
Where,
W is the work done
t is the time taken
We express larger rates of energy transfer in kilowatts (kW).
 
Conservation of Energy: Simple Pendulum
Energy exists in several forms and can be converted from one form into another, but it cannot be destroyed. This is called the conservation of energy.
The total mechanical energy in a system is the sum of its PE and KE.

Question. If a light body and heavy body have same kinetic energy, then which one has greater linear momentum?
(a) Lighter body
(b) Heavier body
(c) Both have same momentum
(d) Can’t be predicted

Answer: B

Question. The speed of an object of mass m dropped from an inclined plane (frictionless), at the bottom of the plane, depends on:
(a) height of the plane above the ground
(b) angle of inclination of the plane
(c) mass of the object
(d) All of these

Answer: A

Question. Work done by a conservative force is positive if
(a) P.E. of the body increases
(b) P.E. of the body decreases
(c) K.E. of the body increases
(d) K.E. of the body decreases

Answer: B

Question. Four particles given, have same momentum. Which has maximum kinetic energy
(a) Proton
(b) Electron
(c) Deutron
(d) α-particles

Answer: B

Question. Which of the following force(s) is/are non-conservative?
(a) Frictional force
(b) Spring force
(c) Elastic force
(d) All of these

Answer: A

Question. The ...X... energy V(x) of the spring is said to be zero when block and spring system is in the ...Y... position.Here, X and Y refer to
(a) potential, equilibrium
(b) kinetic, equilibrium
(c) mechanical, equilibrium
(d) vibrational, left

Answer: A

Question. Which of the diagrams shown in figure most closely shows the variation in kinetic energy of the earth as it moves once around the sun in its elliptical orbit? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-e

Answer: D

Question. A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to
(a) x
(b) ex
(c) x2
(d) loge x

Answer: C

Question. A body of mass 0.5 kg travels in a straight line with velocity v = a x3/2 where a = 5 m–1/2s–1. The work done by the net force during its displacement from x = 0 to x = 2 m is
(a) 15 J
(b) 50 J
(c) 10 J
(d) 100 J

Answer: B

Question. A particle of mass 10 kg moving eastwards with a speed 5 ms–1 collides with another particle of the same mass moving north-wards with the same speed 5 ms–1. The two particles coalesce on collision. The new particle of mass 20 kg will move in the north-east direction with velocity
(a) 10 ms–1
(b) 5 ms–1
(c) (5 /√2)ms-1
(d) none of these

Answer: C

Question. A metal ball of mass 2 kg moving with a velocity of 36 km/h has a head on collision with a stationary ball of mass 3 kg. If after the collision, the two balls move together, the loss in kinetic energy due to collision is
(a) 140 J
(b) 100 J
(c) 60 J
(d) 40 J

Answer: C

Question. Two masses ma and mb moving with velocities va and vb in opposite direction collide elastically and after the collision ma and mb move with velocities Vb and Va respectively. Then the ratio ma/mb is
(a) Va - Vb/Va + Vb
(b) ma+mb/ma
(c) 1
(d) 1/2

Answer: C

Question. A rubber ball is dropped from a height of 5m on a plane, where the acceleration due to gravity is not shown. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of
(a) 16/25
(b) 2/5
(c) 3/5
(d) 9/25

Answer: B

Question. A 10 m long iron chain of linear mass density 0.8 kg m–1 is hanging freely from a rigid support. If g = 10 ms–2, then the power required to left the chain upto the point of support in 10 second
(a) 10 W
(b) 20W
(c) 30 W
(d) 40 W

Answer: D

Question. A 3 kg ball strikes a heavy rigid wall with a speed of 10 m/ s at an angle of 60º. It gets reflected with the same speed and angle as shown here. If the ball is in contact with the wall for 0.20s, what is the average force exerted on the ball by the wall? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-e
(a) 150 N
(b) Zero
(c) 150√3N
(d) 300 N

Answer: C

Question. A bomb of mass 1 kg is thrown vertically upwards with a speed of 100 m/s. After 5 seconds it explodes into two fragments.
One fragment of mass 400 gm is found to go down with a speed of 25 m/s. What will happen to the second fragment just after the explosion? (g = 10 m/s2)
(a) It will go upward with speed 40 m/s
(b) It will go upward with speed 100 m/s
(c) It will go upward with speed 60 m/s
(d) It will also go downward with speed 40m/s

Answer: B

Question. In a simple pendulum of length l the bob is pulled aside from its equilibrium position through an angle q and then released. The bob passes through the equilibrium position with speed
(a) √2gl(1+ cos θ)
(b) √2gl sin θ
(c) √2gl
(d) √2gl(1- cos θ)

Answer: D

Question. A stationary particle explodes into two particles of masses m1 and m2 which move in opposite directions with velocities v1 and v2. The ratio of their kinetic energies E1/E2 is
(a) m1v2/m2v1
(b) m2/m1
(c) m1/m2
(d) 1

Answer: B

Question. Two particles A and B, move with constant velocities v̅1 and v̅2 . At the initial moment their position vectors are r̅1 and r̅2 respectively. The condition for particles A and B for their collision is: 
cbse-class-11-physics-work-energy-and-power-worksheet-set-e

Answer: D

Question. An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms–1 and the second part of mass 2 kg moves with speed 8 ms–1. If the third part flies off with speed 4 ms–1 then its mass is
(a) 5 kg
(b) 7 kg 
(c) 17 kg
(d) 3 kg

Answer: A

Question. A mass of 0.5 kg moving with a speed of 1.5 m/s on a horizontal smooth surface, collides with a nearly weightless spring of force constant k = 50 N/m. The maximum compression of the spring would be
(a) 0.5 m
(b) 0.15 m
(c) 0.12 m
(d) 1.5m

Answer: B

Question. A ball moving with velocity 2 m/s collides head on with another stationary ball of double the mass. If the coefficient of restitution is 0.5, then their velocities (in m/s) after collision will be
(a) 0, 1
(b) 1, 1
(c) 1, 0.5
(d) 0, 2

Answer: A

Question. If v be the instantaneous velocity of the body dropped from the top of a tower, when it is located at height h, then which of the following remains constant ?
(a) gh + v2
(b) gh + v2/2
(c) gh - v2/2
(d) gh – v2

Answer: B

Question. A nucleus moving with a velocity v̅ emits an α- particle. Let the velocities of the a-particle and the remaining nucleus be v̅1 and v̅2 and their masses be m1 and m2.
(a) v̅,v̅1 and v̅2 must be parallel to each other
(b) None of the two of v̅ , v̅and v̅2 should be parallel to each other.
(c) m1 v̅1 + m2 v̅2 must be parallel to (m1+m2)v̅.
(d) None of these

Answer: C

Question. A force acts on a 30 gm particle in such a way that the position of the particle as a function of time is given by x = 3t – 4t2 + t3, where x is in metres and t is in seconds. The work done during the first 4 seconds is
(a) 576 mJ
(b) 450 mJ
(c) 490 mJ
(d) 530 mJ

Answer: A

Question. If the mass of the body is halved and velocity gets doubled then final kinetic energy would be .........of initial.
(a) same
(b) four times
(c) double
(d) eight times

Answer: C

Question.  If two particles are brought near one another, the potential energy of the system will
(a) increase
(b) decrease
(c) remains the same
(d) equal to the K.E

Answer: A

Question. A particle is taken round a circle by application of force. The work done by the force is
(a) positive non–zero
(b) negative non–zero
(c) Zero
(d) None of the above

Answer: C

Question. Which of the following is correct?
(a) W = FS cos θ
(b) P. E. = mgh
(c) K. E. =1/2 mv2
(d) All of these

Answer: D

Question. The potential energy of a system increases if work is done
(a) upon the system by a non conservative force
(b) by the system against a conservative force
(c) by the system against a non conservative force
(d) upon the system by a conservative force

Answer: D

Question. The total mechanical energy of a system is conserved if the force, doing work on it is
(a) constant
(b) variable
(c) conservative
(d) non-conservative

Answer: C

Question. Two bodies of different masses are moving with same kinetic energy. Then the ratio of their momenta is equal to the ratio of their
(a) masses
(b) square of masses
(c) square root of masses
(d) cube root of masses

Answer: C

Question. If stretch in a spring of force constant k is doubled then the ratio of elastic potential energy in the two cases will be
(a) 4 : 1
(b) 1 : 4
(c) 2 : 1
(d) 1 : 2

Answer: A

Question. The energy stored in wounded spring watch is
(a) Kinetic
(b) Potential
(c) Heat
(d) chemical

Answer: B

Question. The temperature at the bottom of a high water fall is higher than that at the top because
(a) by itself heat flows from higher to lower temperature
(b) the difference in height causes a difference in pressure
(c) thermal energy is transformed into mechanical energy
(d) mechanical energy is transformed into thermal energy.

Answer: D

Question. Law of conservation of energy states that
(a) work done is zero
(b) energy is zero
(c) work done is constant
(d) energy of world is constant

Answer: D

Question. The potential energy of a system increases if work is done
(a) upon the system by a non conservative force
(b) by the system against a conservative forc
(c) by the system against a non conservative force
(d) upon the system by a conservative force

Answer: D

Question-  When two bodies stick together after collision, the collision is said to be

(a) partially elastic

(b) elastic

(c) inelastic

(d) perfectly inelastic

Answer-(d)

 

Question-  If a force F is applied on a body and it moves with a velocity V, the power will be

(a) F×v

(b) F/v

(c) F/v2

(d) F×v2

Answer-(a)

 

Question-  Consider the elastic collision of two bodies A and B of equal mass. Initially B is at rest and A moves with velocity v. After the collision

(a) the body A traces its path back with the same speed

(b) the body A comes to rest and B moves away in the direction of A’s approach with the velocity v

(c) both the bodies stick together and are at rest

(d) B moves along with velocity v/2 and A retraces its path with velocity v/2.

Answer-(b)

 

Question- In an inelastic collision

(a) momentum is not conserved

(b) momentum is conserved but kinetic energy is not conserved

(c) both momentum and kinetic energy are conserved

(d) neither momentum nor kinetic energy is conserved

Answer-(b)

 

Question- Which of the following must be known in order to determine the power output of an automobile?

(a) Final velocity and height

(b) Mass and amount of work performed

(c) Force exerted and distance of motion

(d) Work performed and elapsed time of work

Answer-(d)

 

Question- The principle of conservation of linear momentum can be strictly applied during a collision between two particles provided the time of impact

(a) is extremely small

(b) is moderately small

(c) is extremely large

(d) depends on particular case

Answer-(a)

 

Question-  Which one of the following statements is true?

(a) Momentum is conserved in elastic collisions but not in inelastic collisions

(b) Total kinetic energy is conserved in elastic collisions but momentum is not conserved in elastic collisions

(c) Total kinetic energy is not conserved but momentum is conserved in inelastic collisions

(d) Kinetic energy and momentum both are conserved in all types of collisions

Answer-(c)

 

Question- In case of elastic collision, at the time of impact.

(a) total K.E. of colliding bodies is conserved.

(b) total K.E. of colliding bodies increases

(c) total K.E. of colliding bodies decreases

(d) total momentum of colliding bodies decreases.

Answer-(c)

 

Question-  In an inelastic collision, which of the following does not remain conserved?

(a) Momentum

(b) kinetic energy

(c) Total energy

(d) Neither momentum nor kinetic energy

Answer-(b)

 

Question- The coefficient of restitution e for a perfectly inelastic collision is

(a) 1

(b) 0

(c) ∞

(d) –1

Answer-(b)

 

Question- In a one-dimensional elastic collision, the relative velocity of approach before collision is equal to

(a) sum of the velocities of the bodies

(b) e times the relative velocity of separation after collision

(c) 1/e times the relative velocity of separation after collision

(d) relative velocity of separation after collision

Answer-(d)

 

Question-  If a shell fired from a cannon, explodes in mid air, then

(a) its total kinetic energy increases

(b) its total momentum increases

(c) its total momentum decreases

(d) None of these

Answer-(a)

 

Question- When two spheres of equal masses undergo glancing elastic collision with one of them at rest, after collision they will move

(a) opposite to one another

(b) in the same direction

(c) together

(d) at right angle to each other

Answer-(d)

 

Question- The coefficient of restitution e for a perfectly elastic collision is

(a) 1

(b) 0

(c) ∞

(d) –1

Answer-(a)

 

Question- Unit of power is

(a) kilowatt hour

(b) kilowatt/hour

(c) watt

(d) erg

Answer-(c)

 

Question- When after collision the deformation is not relived and the two bodies move together after the collision, it is called

(a) elastic collision

(b) inelastic collision

(c) perfectly inelastic collision

(d) perfectly elastic collision

Answer-(c)

Question. A smooth sphere of mass M moving with velocity u directly collides elastically with another sphere of mass m at rest. After collision, their final velocities are V and v respectively. The value of v is
(a) 2uM/m
(b) 2um/M
(c) 2u/1+m/M
(d) 2u/1+M/m

Answer: C

Question. A shell is fired from a cannon with a velocity V at an angle q with the horizontal direction. At the highest point in its path, it explodes into two pieces of equal masses. One of the pieces retraces its path to the cannon. The speed of the other piece immediately after the explosion is
(a) 3 V cos θ
(b) 2 V cos θ
(c) 3/2 Vcos θ
(d) V cos θ

Answer: A

Question. An electron and a proton are moving under the influence of mutual forces. In calculating the change in the kinetic energy of the system during motion, one ignores the magnetic force of one on another. This is, because
(a) the two magnetic forces are equal and opposite, so they produce no net effect
(b) the magnetic forces do not work on each particle
(c) the magnetic forces do equal and opposite (but nonzero) work on each particle
(d) the magnetic forces are necessarily negligible

Answer: B

Question. A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particle is also a proton and in another, a positron. In the same time t, the work done on the two moving charged particles is
(a) same as the same force law is involved in the two experiments
(b) less for the case of a positron, as the positron moves away more rapidly and the force on it weakens
(c) more for the case of a positron, as the positron moves away a larger distance
(d) same as the work done by charged particle on the stationary proton.

Answer: C

Question. The kinetic energy of particle moving along a circle of radius R depends upon the distance covered S and is given by K = aS where a is a constant. Then the force acting on the particle is
(a) aS/R
(b) 2(aS)2/R
(c) aS2/R2
(d) 2aS/R

Answer: D

Question. The potential energy of particle in a force field is U = A/r2 - B/r , where A and B are positive constants and r is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is
(a) B / 2A
(b) 2A / B
(c) A / B
(d) B / A

Answer: B

Question. A body is falling freely under the action of gravity alone in vaccum. Which of the following quantities remain constant during the fall?
(a) Kinetic energy
(b) Potential energy
(c) Total mechanical energy
(d) Total linear momentum

Answer: C

Question. Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take 'g' constant with a value 10 m/s2.
The work done by the (i) gravitational force and the (ii) resistive force of air is 
(a) (i) 1.25 J (ii) –8.25 J
(b) (i) 100 J (ii) 8.75 J
(c) (i) 10 J (ii) – 8.75 J
(d) (i) – 10 J (ii) –8.25 J

Answer: C

Question. A particle of mass m is driven by a machine that delivers a constant power of k watts. If the particle starts from rest the force on the particle at time t is
(a) √mk t–1/2
(b) √2mk t–1/2
(c) 1/2√2mk t–1/2
(d) √mk/2 t–1/2

Answer: D

Question. During inelastic collision between two bodies, which of the following quantities always remain conserved?
(a) Total kinetic energy
(b) Total mechanical energy
(c) Total linear momentum
(d) Speed of each body

Answer: C

Question. Two inclined frictionless tracks, one gradual and the other steep meet at A from where two stones are allowed to slide down from rest, one on each track as shown in figure.
Which of the following statement is correct? 
(a) Both the stones reach the bottom at the same time but not with the same speed
(b) Both the stones reach the bottom with the same speed and stone I reaches the bottom earlier than stone II
(c) Both the stones reach the bottom with the same speed and stone II reaches the bottom earlier than stone I
(d) Both the stones reach the bottom at different times and with different speeds

Answer: C

Question. The ball rolls down without slipping (which is at rest at a) along ab having friction. It rolls to a maximum height hc where bc has no friction. Ka, Kb and Kc are kinetic energies at a, b and c. Which of the following is correct ? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-g
(a) Ka = Kc, ha = hc
(b) Kb > Kc, ha = hc
(c) Kb > Kc, ha < hc
(d) Kb > Kc, ha > hc

Answer: D

Question. A train of weight 107 N is running on a level track with uniform speed of 36 km h–1. The frictional force is 0.5 kg per quintal. If g = 10 m/s2, then power of engine is
(a) 500 kW
(b) 50 kW
(c) 5 kW
(d) 0.5 kW

Answer: A

Question. The potential energy function for a particle executing linear SHM is given by V(x) = 1/2kx2 where k is the force constant of the oscillator (Fig.). For k = 0.5 N/m, the graph of V(x) versus x is shown in the figure. A particle of total energy E turns back when it reaches x = ±xm. If V and K indicate the PE and KE, respectively of the particle at x = +xm, then which of the following is correct? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-g
(a) V = O, K = E
(b) V = E, K = O
(c) V < E, K = O
(d) V = O, K < E

Answer: B

Question. A raindrop falling from a height h above ground, attains a near terminal velocity when it has fallen through a height (3/4)h. Which of the diagrams shown in figure correctly shows the change in kinetic and potential energy of the drop during its fall up to the ground? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-g

Answer: B

Question. A uniform force of (3î + ĵ) newton acts on a particle of mass 2 kg. The particle is displaced from position (2î + k̂) meter to position (4î + 3ĵ - k̂) meter. The work done by the force on the particle is
(a) 6 J
(b) 13 J
(c) 15 J
(d) 9 J

Answer: D

Question. Which of the diagrams in figure correctly shows the change in kinetic energy of an iron sphere falling freely in a lake having sufficient depth to impart it a terminal velocity? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-g

Answer: B

Question. The coefficient of friction between the tyres and the road is m. A car is moving with momentum p. What will be the stopping distance due to friction alone ? The mass of the
car is m.
(a) p2/2μg
(b) p2/2mμg
(c) p2/2m2μg
(d) p2/2mg

Answer: C

Question. If the kinetic energy of a body is increased by 300%, the momentum of the body is increased by
(a) 300%
(b) 200%
(c) 100%
(d) 50%

Answer: C

Question. A cricket ball of mass 150 g moving with a speed of 126 km/ h hits at the middle of the bat, held firmly at its position by the batsman. The ball moves straight back to the bowler after hitting the bat. Assuming that collision between ball and bat is completely elastic and the two remain in contact for 0.001s, the force that the batsman had to apply to hold the bat firmly at its place would be
(a) 10.5 N
(b) 21 N
(c) 1.05 × 104 N
(d) 2.1 × 104 N

Answer: C

Question. A uniform force of (3î + ĵ) newton acts on a particle of mass 2 kg. The particle is displaced from position ((2î + k̂) meter to position (4î + 3ĵ -k̂) meter. The work done by the force on the particle is
(a) 6 J
(b) 13 J
(c) 15 J
(d) 9 J

Answer: D

Question. A man squatting on the ground gets straight up and stand.
The force of reaction of ground on the man during the process is
(a) constant and equal to mg in magnitude
(b) constant and greater than mg in magnitude
(c) variable but always greater than mg
(d) at first greater than mg and later becomes equal to mg

Answer: D

Question. A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally, in 5 s. Each bullet has a mass of 10 g with a muzzle velocity of 800 ms–1. The final velocity acquired by the person and the average force exerted on the person are 
(a) –1.6 ms–1; 8 N
(b) –0.08 ms–1; 16 N
(c) – 0.8 ms–1; 8 N
(d) –1.6 ms–1; 16 N

Answer: C

Question. A particle with total energy E is moving in a potential energy region U(x). Motion of the particle is restricted to the region when 
(a) U(x) > E
(b) U(x) < E
(c) U(x) = O 
(d) U(x) ≤ E

Answer: D

Question. One coolie takes 1 minute to raise a suitcase through a height of 2 m but the second coolie takes 30 s to raise the same suitcase to the same height. The powers of two coolies are in the ratio of 
(a) 1 : 2
(b) 1 : 3
(c) 2 : 1
(d) 3 : 1

Answer: A

Question. An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 ms–1 and the second part of mass 2 kg moves with speed 8 ms–1. If the third part flies off with speed 4 ms–1 then its mass is
(a) 5 kg
(b) 7 kg
(c) 17 kg
(d) 3 kg

Answer: A

Question. In a shotput event an athlete throws the shotput of mass 10 kg with an initial speed of 1 m s–1 at 45° from a height 1.5 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be 10 m s–2, the kinetic energy of the shotput when it just reaches the ground will be
(a) 2.5 J
(b) 5.0 J
(c) 52.5 J
(d) 155.0 J

Answer: D

Question. A body of mass (4m) is lying in x-y plane at rest. It suddenly explodes into three pieces. Two pieces, each of mass (m) move perpendicular to each other with equal speeds (v).
The total kinetic energy generated due to explosion is :
(a) mv2
(b) 3/2 mv2
(c) 2 mv2
(d) 4 mv2

Answer: B

Question. A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8 × 10–4 J by the end of the second revolution after the beginning of the motion ? 
(a) 0.1 m/s2
(b) 0.15 m/s2
(c) 0.18 m/s2
(d) 0.2 m/s2

Answer: A

Question. Two similar springs P and Q have spring constants KP and KQ, such that KP > KQ. They are stretched, first by the same amount (case a,) then by the same force (case b). The work done by the springs WP and WQ are related as, in case (a) and case (b), respectively
(a) WP = WQ ; WP = WQ
(b) WP > WQ ; WQ > WP
(c) WP < WQ ; WQ < WP
(d) WP = WQ ; WP > WQ

Answer: B

Question. A bicyclist comes to a skidding stop in 10 m. During this process, the force on the bicycle due to the road is 200N and is directly opposed to the motion. The work done by the cycle on the road is
(a) + 2000 J
(b) – 200 J
(c) zero
(d) – 20,000 J

Answer: C

Question. The heart of man pumps 5 litres of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury be 13.6 ×103 kg/m3 and g = 10m/s2 then the power of heart in watt is : 
(a) 2.35
(b) 3.0
(c) 1.50
(d) 1.70

Answer: D

Question. A ball is thrown vertically downwards from a height of 20 m with an initial velocity v0. It collides with the ground loses 50 percent of its energy in collision and rebounds to the same height. The initial velocity v0 is : (Take g = 10 ms–2)
(a) 20 ms–1
(b) 28 ms–1
(c) 10 ms–1
(d) 14 ms–1

Answer: A

Question. Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed v as shown in figure. 
cbse-class-11-physics-work-energy-and-power-worksheet-set-h
If the collision is elastic, which of the following (figure) is a possible result after collision? 
cbse-class-11-physics-work-energy-and-power-worksheet-set-h

Answer: B

Question. A mass of 5 kg is moving along a circular path of radius 1 m. If the mass moves with 300 rev/min, its kinetic energy would be
(a) 250 π2
(b) 100 π2
(c) 5 π2
(d) 0

Answer: A

Question. On a frictionless surface a block of mass M moving at speed v collides elastically with another block of same mass M which is initially at rest. After collision the first block moves at an angle θ to its initial direction and has a speed v/3 . The second block's speed after the collision is :
(a) 3/4 v
(b) 3/√2 v
(c) √3/2 v
(d) 2√2/3 v

Answer: D

Question. A block of mass 10 kg, moving in x direction with a constant speed of 10 ms–1, is subject to a retarding force F = 0.1 × J/m uring its travel from x = 20 m to 30 m. Its final KE will be:
(a) 450 J
(b) 275 J
(c) 250 J
(d) 475 J

Answer: D

Question. A body of mass 1 kg begins to move under the action of a time dependent force F̅ = (2tî + 3t2ĵ) N, where î and ĵ are unit vectors alogn x and y axis. What power will be developed by the force at the time t? 
(a) (2t2 + 3t3)W
(b) (2t2 + 4t4)W
(c) (2t3 + 3t4) W
(d) (2t3 + 3t5)W

Answer: D

DIRECTIONS : Each question contains Statement- 1 and Statement-2. Choose the correct answer from the following.
(a) Statement -1 is false, Statement-2 is true
(b) Statement -1 is true, Statement-2 is true; Statement -2 is a correct explanation for Statement-1
(c) Statement -1 is true, Statement-2 is true; Statement -2 is not a correct explanation for Statement-1
(d) Statement -1 is true, Statement-2 is false

Question. Statement -1 : A work done by friction is always negative.
Statement -2 : If frictional force acts on a body its K.E. may decrease.

Answer: A

Question. Statement -1 : An object of mass m is initially at rest. A constant force F acts on it. Then the velocity gained by the object during a fixed displacement is proportional to 1/√m.
Statement -2 : For a given force and displacement velocity is always inversely proportional to root of mass.

Answer: C

Question. Statement -1 : Mechanical energy is the sum of macroscopic kinetic & potential energies.
Statement - 2 : Mechanical energy is that part of total energy which always remain conserved.

Answer: D

Question. Statement-1 : A quick collision between two bodies is more violent than slow collision, even when initial and final velocities are identical.
Statement -2 : The rate of change of momentum determines that the force is small or large.

Answer: B

Question. Statement -1 : If collision occurs between two elastic bodies their kinetic energy decreases during the time of collision.
Statement -2 : During collision intermolecular space decreases and hence elastic potential energy increases.

Answer: B

More Study Material

CBSE Class 11 Physics Chapter 6 Work Energy and Power Worksheet

We hope students liked the above worksheet for Chapter 6 Work Energy and Power designed as per the latest syllabus for Class 11 Physics released by CBSE. Students of Class 11 should download in Pdf format and practice the questions and solutions given in the above worksheet for Class 11 Physics on a daily basis. All the latest worksheets with answers have been developed for Physics by referring to the most important and regularly asked topics that the students should learn and practice to get better scores in their class tests and examinations. Studiestoday is the best portal for Class 11 students to get all the latest study material free of cost.

Worksheet for Physics CBSE Class 11 Chapter 6 Work Energy and Power

Expert teachers of studiestoday have referred to the NCERT book for Class 11 Physics to develop the Physics Class 11 worksheet. If you download the practice worksheet for one chapter daily, you will get higher and better marks in Class 11 exams this year as you will have stronger concepts. Daily questions practice of Physics worksheet and its study material will help students to have a stronger understanding of all concepts and also make them experts on all scoring topics. You can easily download and save all revision worksheet for Class 11 Physics also from www.studiestoday.com without paying anything in Pdf format. After solving the questions given in the worksheet which have been developed as per the latest course books also refer to the NCERT solutions for Class 11 Physics designed by our teachers

Chapter 6 Work Energy and Power worksheet Physics CBSE Class 11

All worksheets given above for Class 11 Physics have been made as per the latest syllabus and books issued for the current academic year. The students of Class 11 can be rest assured that the answers have been also provided by our teachers for all worksheet of Physics so that you are able to solve the questions and then compare your answers with the solutions provided by us. We have also provided a lot of MCQ questions for Class 11 Physics in the worksheet so that you can solve questions relating to all topics given in each chapter. All study material for Class 11 Physics students have been given on studiestoday.

Chapter 6 Work Energy and Power CBSE Class 11 Physics Worksheet

Regular worksheet practice helps to gain more practice in solving questions to obtain a more comprehensive understanding of Chapter 6 Work Energy and Power concepts. Worksheets play an important role in developing an understanding of Chapter 6 Work Energy and Power in CBSE Class 11. Students can download and save or print all the worksheets, printable assignments, and practice sheets of the above chapter in Class 11 Physics in Pdf format from studiestoday. You can print or read them online on your computer or mobile or any other device. After solving these you should also refer to Class 11 Physics MCQ Test for the same chapter.

Worksheet for CBSE Physics Class 11 Chapter 6 Work Energy and Power

CBSE Class 11 Physics best textbooks have been used for writing the problems given in the above worksheet. If you have tests coming up then you should revise all concepts relating to Chapter 6 Work Energy and Power and then take out a print of the above worksheet and attempt all problems. We have also provided a lot of other Worksheets for Class 11 Physics which you can use to further make yourself better in Physics

Where can I download latest CBSE Printable worksheets for Class 11 Physics Chapter 6 Work Energy and Power

You can download the CBSE Printable worksheets for Class 11 Physics Chapter 6 Work Energy and Power for latest session from StudiesToday.com

Can I download the Printable worksheets of Chapter 6 Work Energy and Power Class 11 Physics in Pdf

Yes, you can click on the links above and download Printable worksheets in PDFs for Chapter 6 Work Energy and Power Class 11 for Physics

Are the Class 11 Physics Chapter 6 Work Energy and Power Printable worksheets available for the latest session

Yes, the Printable worksheets issued for Class 11 Physics Chapter 6 Work Energy and Power have been made available here for latest academic session

How can I download the Class 11 Physics Chapter 6 Work Energy and Power Printable worksheets

You can easily access the links above and download the Class 11 Printable worksheets Physics Chapter 6 Work Energy and Power for each chapter

Is there any charge for the Printable worksheets for Class 11 Physics Chapter 6 Work Energy and Power

There is no charge for the Printable worksheets for Class 11 CBSE Physics Chapter 6 Work Energy and Power you can download everything free

How can I improve my scores by solving questions given in Printable worksheets in Class 11 Physics Chapter 6 Work Energy and Power

Regular revision of practice worksheets given on studiestoday for Class 11 subject Physics Chapter 6 Work Energy and Power can help you to score better marks in exams

Are there any websites that offer free test sheets for Class 11 Physics Chapter 6 Work Energy and Power

Yes, studiestoday.com provides all latest NCERT Chapter 6 Work Energy and Power Class 11 Physics test sheets with answers based on the latest books for the current academic session

Can test papers for Class 11 Physics Chapter 6 Work Energy and Power be accessed on mobile devices

Yes, studiestoday provides worksheets in Pdf for Chapter 6 Work Energy and Power Class 11 Physics in mobile-friendly format and can be accessed on smartphones and tablets.

Are worksheets for Chapter 6 Work Energy and Power Class 11 Physics available in multiple languages

Yes, worksheets for Chapter 6 Work Energy and Power Class 11 Physics are available in multiple languages, including English, Hindi