Question

A body is said to be in motion when its position continously changes with respect to stationary object.Exlain this statement.

Answer 1

A body is said to be in motion if its position changes continuously, with respect to a stationary object, taken as reference point, with the passage of time. When we are sitting in a moving bus, we observe the continuous changes of position with respect to stationary object like houses, trees, lamp posts, etc. We say that the bus is moving or that the bus is in motion.

Thus, we can say that an object is in, motion, if it changes ils posilion conlinuously wilh respect lo ils surroundings in a given time. Since the position of desk and benches does not changes with time, hence we can say that they are not in motion, .e. they are stationary. You must have observed sky at night: the position cf stars changes with the passage of time, whereas the position of house and our surrounding remains the same. But in reality the earth is also moving that means all the objects on the surface of the earth are also in motion. Thus, an object which appears to be at rest, may actualy be in motion. Therefore, motion and rest are relative terms. Hence, to describe the motion of an object we have to specify how its position changes with respect to a fixed point cal ec the reference point or origin Without frame of reference we cannot specify whether an object is in motion or at est. A frame of reference is another object or scene with respect to whch we compare an object's position