Chapter 1: Q4Q (page 38)

Place a ball on a book and walk with the book in uniform motion. Note that you don't really have to do anything to the ball to keep the ball moving with constant velocity (relative to the ground) or to keep the ball at rest (relative to you). Then stop suddenly, or abruptly change your direction or speed. What does Newton's first law of motion predict for the motion of the ball (assuming that the interaction between the ball and the book is small)? Does the ball behave as predicted? It may help to take the point of view of a friend who is standing still, watching you.

Short Answer

Expert verified

The ball behaves just like Newton’s first law predicted. But it also experiences friction, gravity and air resistance. These forces try to stop the ball.

Step by step solution

Given data

Here given is a ball that is placed on a book and a person walking holding that book.

Definition of Newton’s First law of motion

The first law of Newton's states that if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.

Observation and conclusion

Newton’s first law predict that the ball will keep its state of motion (constant speed in a straight line), and indeed it will try to keep going with the same speed and in the same direction.

Therefore, the ball behaves just like Newton’s first law predicted but friction, gravity and air resistance will try to stop it.