Question

How to measure motion?

Answer 1

Motion

1. Motion is an action of a body when it is in movement.
2. Motion can be measured by velocity or speed.
3. Change with time in the position of a body is the effect of motion.
4. All moving objects surrounding us like vehicles, cricket balls, and boats are examples of motion.

Measurement of motion

1. To measure motion, we have to find out its position, speed
2. Speed is the rate of change in distance.
3. $speed=\frac{dis\tan ce}{totaltimetaken}$
4. If speed = zero, then the body is at rest.
5. So speed gives the idea that a body is in motion or at rest.
6. Measurement of motion is relative. If an observer is at rest in his or her own frame of reference, but he may be moving in another observer's frame of reference.
7. If we consider a box and a person in a bus, the box is stationary with respect to the person in the bus. But if we consider the view of a person standing outside, the box is in motion. Here the motion is relative.

Diagram

Thus, speed is the measure of motion.