CBSE Class 11 Physics Motion Of System Of Particles Notes Set A

                                                   Physics Motion Of System Of Particles And Rigid Body

1. If one of the particles is heavier than the other, to which will their centre of mass shift? Answer:- The centre of mass will shift closer to the heavier particle.

2. Can centre of mass of a body coincide with geometrical centre of the body? Answer:- Yes, when the body has a uniform mass density.

3.Which physical quantity is represented by a product of the moment of inertia and the angular velocity? Answer:- Product of I and ω represents angular momentum(L=I ω).

4. Which component of linear momentum does not contribute to angular momentum? Answer:- The radial component of linear momentum makes no contribution to angular momentum.

5. What are factors on which moment of inertia depend upon? Answer:- Moment of inertia of a body depends on position and orientation of the axis of rotation. It also depends on shape, size of the body and also on the distribution of mass of the body about the given axis.

6. Is radius of gyration of a body constant quantity? Answer:- No, radius of gyration of a body depends on axis of rotation and also on distribution of mass of the body about the axis.

7. Is the angular momentum of a system always conserved? If no, under what condition is it conserved? Answer:- No, angular momentum of a system is not always conserved. It is conserved only when no external torque acts on the system

2 Marks Questions

1. Why is the handle of a screw made wide? Answerwer:- Turning moment of a force= force × distance(r) from the axis of rotation. To produce a given turning moment, force required is smaller, when r is large. That’s whathappens when handle of a screw is made wide.

2. A person is sitting in the compartment of a train moving with uniform velocity on a smooth track. How will the velocity of centre of mass of compartment change if the person begins to run in the compartment? Answer:- We know that velocity of centre of mass of a system changes only when an external force acts on it. The person and the compartment form one system on which no external force is applied when the person begins to run. Therefore, there will be no change in velocity of centre of mass of the compartment

3. Why there are two propellers in a helicopter? Answerwer:- If there were only one propeller in a helicopter then, due to conservation of angular momentum, the helicopter itself would have turned in the opposite direction.

Please refer to attached file for CBSE Class 11 Physics Motion Of System Of Particles