Question

Define the following.
1. Length
2. Motion
3. Periodic motion
4. Rotational motion

Answer 1

1. Length
The distance of something from one end to the other is called length.

2. Motion
An object is said to be in motion if its position (with respect to another object) changes with time.

3. Periodic motion
A motion that repeats itself after equal intervals of time is called periodic motion.

4. Rotational motion
When an object moves about an axis and different parts of it move by different distances in a given interval of time, it is said to be in rotational motion.