Question

Can a body be both at rest as well as in motion? Explain.

Answer 1

1. Rest and motion are relative terms.
2. A body at rest with respect to one observer may be in motion with respect to another observer.
3. 
4. For example, A person sitting on a moving train is at rest with respect to the train. He is in motion with respect to a person standing outside.
5. We think that we are at rest but we are actually in motion as the earth itself is moving with respect to the Sun. With respect to the earth, we are at rest (if we are stationary) but with respect to the sun, we are moving.
6. Imagine yourself sitting inside a moving car. A person sitting beside you would consider you to be at rest. However, a person standing outside would see you moving along with the car. To him/her you would be in a state of motion.
7. Hence, a body can be both at rest as well as in motion.