H C Verma Solutions for Chapter: Centre of Mass, Linear Momentum, Collision, Exercise 1: QUESTIONS FOR SHORT ANSWER

A bob suspended from the ceiling of a car which is accelerating on a horizontal road. The bob stays at rest with respect to the car with the string making an angle $\mathrm{\theta }$ with the vertical. The linear momentum of the bob as seen from the road is increasing with time. Is it a violation of conservation of linear momentum? If not, where is the external force changes the linear momentum?

You are waiting for a train on a railway platform. Your three-year-old niece is standing on your iron trunk containing the luggage. Why does the trunk not recoil as she jumps off on the platform?

A collision experiment is done on a horizontal table kept in an elevator. Do you expect a change in the result if the elevator is accelerated up or down because of the non-inertial character of the frame?

A fat person is standing on a light plank floating on a calm lake. The person walks from one end to the other on the plank. His friend sitting on the shore watches him and finds that the person hardly moves any distance because the plank moves backward about the same distance as the person moves on the plank. Explain.

Which of the two persons shown in figure is more likely to fall down? Which external force is responsible for his falling down?

Suppose, we define a quantity 'Linear Momentum' as $\mathrm{linear} \mathrm{momentum}=\mathrm{mass} \times \mathrm{speed}.$ Can we state the principle of conservation of linear momentum for a single particle?

A van is standing on a frictionless portion of a horizontal road. To start the engine, the vehicle must be set in motion in the forward direction. How can the persons sitting inside the van do it without coming out and pushing from behind?

In one-dimensional elastic collision of equal masses, the velocities are interchanged. Can velocities in a one-dimensional collision be interchanged if the masses are not equal?