JEE Physics Motion In A Plane MCQs Set A

Question: Which of the following is a vector?

• a) Acceleration
• b) Volume
• c) Time
• d) Current

Answer: Acceleration

Question: The change in a vector may occur due to

• a) Rotation of vector
• b) Rotation of frame of reference
• c) Translation of frame of reference
• d) None of this

Answer: Rotation of vector

Question: Which one of the following pair cannot be the rectangular components of force vector of 10 N?

• a) 9 N & 1 N
• b) 6 N & 8 N
• c) Both
• d) None of this

Answer: 9 N & 1 N

Question: The resultant of two vectors at an angle 150° is 10 units and is perpendicular to one vector. The magnitude of the smaller vector is

• a)

  

• b)

  

• c)

  

• d) 10 units

Answer:

Question: Two vectors, each of magnitude A have a resultant of same magnitude A. The angle between the two vectors is

• a) 120°
• b) 150°
• c) 60°
• d) 30°

Answer:  120°

Question:

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question:

• a) 10.8 units due east
• b) 2.7 units due east
• c) 4 units due west
• d) 4 units due east

Answer: 10.8 units due east

Question: Two forces of magnitude 8 N and 15 N respectively act at a point. If the resultant force is 17 N, the angle between the forces has to be

• a) 30°
• b) 90°
• c) 45°
• d) 60°

Answer: 30°

Question: A particle is moving in a circle of radius r having centre at O, with a constant speed v. The magnitude of change in velocity in moving from A to B is

• a) v
• b) 0
• c) 2v
• d)

  

Answer: v

Question: Two forces of 10 N and 6 N act upon a body. The direction of the forces are unknown. The resultant force on the body may be

• a) 15 N
• b) 3 N
• c) 17 N
• d) 2 N

Answer:  15 N

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: If the sum of two unit vectors is also a unit vector, then magnitude of their difference and angle between the two given unit vectors is

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question:

• a) Along west
• b) Vertically downward
• c) Along east
• d) Zero

Answer: Along west

Question:

• a) 9
• b) –9
• c) 3
• d) –8

Answer:  9

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question: If resultant of two vectors having magnitude 3 and 4 is 5. The magnitude of their cross product is

• a) 12
• b) 18
• c) 15
• d) 20

Answer: 12

Question:

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) All of this

Answer:

Question:

• a) y = 2x²
• b) y = x²
• c)

  

• d) None of This

Answer: y = 2x²

Question: Ram moves in east direction at a speed of 6 m/s and Shyam moves 30° east of north at a speed of 6 m/s. The magnitude of their relative velocity is

• a) 6 m/s
• b) 3 m/s
• c)

  

• d) All of these

Answer: 6 m/s

Question:  A train is running at a constant speed of 90 km/h on a straight track. A person standing at the top of a boggey moves in the direction of motion of the train such that he covers 1 meters on the train each second. The speed of the person with respect to ground is

• a) 26 km/h
• b) 26 m/s
• c) 91 km/h
• d) 25 m/s

Answer:  26 km/h

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Four persons P, Q, R and S are initially at the four corners of a square of side d. Each person now moves with a constant speed v in such a way that P always moves directly towards Q, Q towards R, R towards S, and S towards P. The four persons will meet after time

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question: A person, reaches a point directly opposite on the other bank of a flowing river, while swimming at a speed of 5 m/s at an angle of 120° with the flow. The speed of the flow must be

• a) 2.5 m/s
• b) 3 m/s
• c) 4 m/s
• d) 1.5 m/s

Answer: 2.5 m/s

Question: A body of mass 1 kg is projected from ground at an angle 30º with horizontal on a level ground at a speed 50 m/s. The magnitude of change in momentum of the body during its flight is (g = 10 m/s2)

• a) 50 kg ms^–1
• b) 100 kg ms^–1
• c) 25 kg ms^–1
• d) 0

Answer: 50 kg ms^–1

Question: A boat which has a speed of 5 km/hr in still water crosses a river of width 1 km along the shortest possible path in 15 minutes. The velocity of the river water (in km/hr) is

• a) 3
• b) 4
• c) 40
• d) 2

Answer: 3

Question: A car with a vertical windshield moves in a rain storm at a speed of 40 km/hr. The rain drops fall vertically with constant speed of 20 m/s. The angle at which rain drops strike the windshield is

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) All of these

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The position coordinates of a projectile projected from ground on a certain planet (with no atmosphere) are given by y = (4t – 2t²)m and x = (3t) metre, where t is in second and point of projection is taken as origin. The angle of projection of projectile with vertical is

• a) 37°
• b) 30°
• c) 45°
• d) 60°

Answer: 37°

Question:

• a) 40 m/s
• b) Zero
• c)

  

• d) None of this

Answer:  40 m/s

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Two objects are thrown up at angles of 45° and 60° respectively, with the horizontal. If both objects attain same vertical height, then the ratio of magnitude of velocities with which these are projected is

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A projectile is thrown into space so as to have a maximum possible horizontal range of 400 metres. Taking the point of projection as the origin, the co-ordinates of the point where the velocity of the projectile is minimum are

• a) (200, 100)
• b) (400, 100)
• c) (400, 200)
• d) (200, 200)

Answer: (200, 100)

Question: If the time of flight of a bullet over a horizontal range R is T, then the angle of projection with horizontal is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In the graph shown in figure, which quantity associated with projectile motion is plotted along y-axis

• a) Horizontal velocity
• b) Momentum
• c) Kinetic energy
• d) None of these

Answer: Horizontal velocity

Question: The equation of a projectile is y = ax – bx². Its horizontal range is

• a)

  

• b)

  

• c) a + b
• d) b – a

Answer:

Question: Figure shows a projectile thrown with speed u = 20 m/s at an angle 30° with horizontal from the top of a building 40 m high. Then the horizontal range of projectile is

• a)

  

• b)

  

• c) 40 m
• d) 50 m

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In the given figure for a projectile

• a)

  

• b)

  

• c)

  

• d) All of this

Answer:

Question: Two paper screens A and B are separated by distance 100 m. A bullet penetrates A and B, at points P and Q respectively, where Q is 10 cm below P. If bullet is travelling horizontally at the time of hitting A, the velocity of bullet at A is nearly

• a) 700 m/s
• b) 600 m/s
• c) 200 m/s
• d) 100 m/s

Answer:  700 m/s

Question:

• a)

  

• b)

  

• c)

  

• d) None of this

Answer:

Question: A body revolves with constant speed v in a circular path of radius r. The magnitude of its average acceleration during motion between two points in diametrically opposite direction is

• a)

  

• b)

  

• c)

  

• d) 0

Answer:

Question: An object of mass m moves with constant speed in a circular path of radius R under the action of a force of constant magnitude F. The kinetic energy of object is

• a)

  

• b) FR
• c) 2FR
• d)

  

Answer:

Question: The angular speed of earth around its own axis is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A particle moves in a circle of radius 25 cm at two revolutions per second. The acceleration of the particle is (in m/s2)

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A particle is revolving in a circular path of radius25 m with constant angular speed 12 rev/min. Then the angular acceleration of particle is

• a) 0
• b)

  

• c)

  

• d)

  

Answer: 0

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: A particle P is moving in a circle of radius r with uniform speed v. C is the centre of the circle and AB is diameter. The angular velocity of P about A and C is in the ratio

• a) 2 : 1
• b) 4 : 1
• c) None of this
• d) 1 : 2

Answer: 2 : 1

Question: A car is moving at a speed of 40 m/s on a circular track of radius 400 m. This speed is increasing at the rate of 3 m/s². The acceleration of car is

• a) 5 m/s²
• b) 3 m/s²
• c) 7 m/s²
• d) 4 m/s²

Answer: 5 m/s²

Question: Four particles A, B, C and D are moving with constant speed v each. At the instant shown relative velocity of A with respect to B, C and D are in directions

• a)

  

• b)

  

• c)

  

• d) None of This

Answer:

Question: The ratio of angular speeds of minute hand and hour hand of a watch is

• a) 12 : 1
• b) 6 : 1
• c) 60 : 1
• d) 1 : 60

Answer:  12 : 1

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: If speed of an object revolving in a circular path is doubled and angular speed is reduced to half of original value, then centripetal acceleration will become/remain

• a) Half
• b) Quadruple
• c) Double
• d) Same

Answer: Half

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer: