Chapter 15, Problem 21A

If you were in a smooth-riding train with no windows, could you sense the difference between uniform motion and rest? Between accelerated motion and rest? Explain how you could do this with a bowl filled with water.

To determine

Whether one could sense the difference between the uniform motion or accelerated motion and rest.

No, the difference between the uniform motion and rest could not be sensed while the difference between accelerated motion and rest could be sensed.

Answer to Problem 21A

No, the difference between the uniform motion and rest could not be sensed while the difference between accelerated motion and rest could be sensed.

Explanation of Solution

Introduction:

When the object is moving in a straight line with a constant velocity and covers equal distance in equal intervals of time, then the object is said to have uniform motion.

If the velocity of the object changes then the object is said to have accelerated motion.

One can sense the difference between uniform motion and rest only when one is looking at the objects around one while moving. But in the given situation, there are no windows. Hence, one cannot sense the difference between the uniform motion and rest.

If one considers an example of a bowl of water, then due to accelerated motion the water level will get disturbed. Hence, one could sense the difference between the accelerated motion and rest.

Conclusion:

Thus, the difference between the uniform motion and rest could not be sensed while the difference between accelerated motion and rest could be sensed.