PHYSICS [3 Mark Question Answer]

The different types of motion are :
1. Translatory motion
2. Rotatory motion
3. Oscillatory motion
4. Vibratory motion
5. Periodic motion
6. Multiple motion
7. Random motion.

Mass
It is the quantity of mattercontained in a body.
Its S.J. unit is kilogram (kg)
It is constant for a body and it does not change by changing the place of the body.
It is measured by a beam balance.
Weight
It is the force with which the earth attracts the body.
Its S.I. unit is newton (N) and other unit is kilogram-force (kgf) where 1 kgf= 1ON(nearly).
It is not constant for a body, but it changes from place to place.
It is measured by a spring balance.

Sometime a body can have more than one type of motion. Such a motion is called the mixed motion.
Example :
(i) The wheels of a moving train have both the translatory as well as the rotatory motions as it moves from position A to position B while rotating.

(ii) The earth rotates about its axis (rotatory motion) and at the same time it revolves around the sun in a curved path (curvilinear or circular motion) in a fixed time interval (periodic motion).

Periodic motion : A motion which gets repeated after regular intervals of time is called periodic motion.
Examples: The earth moving around the sun takes 365 days to complete one revolution and this motion gets repeated after every 365 days.
Non-periodic motion: The motion which does not repeat itself after a regular interval of time is called non-periodic motion.
Examples: A footballer running on a field, application of brakes in a moving vehicle, a ball rolling down the ground gradually slows down and finally stops, the motion of tides in the sea, etc.