Classify the following as the motion along a straight line, circular or oscillatory motion.
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry go round.
(iv) Motion of a child on a see-saw.
(v) Motion of a hammer of an electric bell.
(vi) Motion of a train on a straight bridge.

Hint: We have to study the examples of motion given and then understand that motion so that we can classify the given examples if these are of circular, straight line or oscillatory. Straight line is the motion in which the object or body moves in the straight line, circular motion is described as the motion of an object or a body on a circular path and oscillatory motion is the periodic motion of the body or an object.

Complete answer:
(i) Motion of hands while running is to and fro like a pendulum. Pendulum represents the periodic motion thus, we concluded that the motion of our hands while running is oscillatory motion.

(ii) Straight road represents a straight line. So here a horse pulling a cart on a straight road is called the straight line motion.

(iii) Merry go round is circular and when a child sits on the merry go round at one point and returns to the same place when it completes one round. This motion is circular as round refers to a circle.

(iv) See-saw is the process of going up and then down like we see in a pendulum when it reaches from mean to extrema and extremum to mean this means it is periodic motion like a pendulum. Thus, a child on a see-saw is an example of oscillatory motion.

(v) This is also like to and fro motion like a pendulum. Thus the hammering of an electric bell is also an oscillatory motion.

(vi) Train on a straight bridge is in straight line motion because the train is running on a straight bridge like a straight line.

Note: Here, we understood the motions and their characteristics that is why we have classified these examples into different forms of motion straight line, circular and oscillatory. The motions are described by their names only and there we understood the meaning of these motions.