Question

A to and fro motion by an object is also called
A. Periodic motion
B. Oscillatory motion
C. Cyclic motion
D. None of these

Answer 1

Recall the definition of every given option. When the particle vibrates or oscillates about its mean position, the motion is said to be the to and fro motion. In periodic motion and cyclic motion the particle repeats after a regular interval of time.

Complete answer:
Let us define the to and fro motion of the particle. When the particle vibrates or oscillates about its mean position, the motion is said to be the to and fro motion. To answer this question, let us check every option as follows,

Periodic motion: We know that in periodic motion, the particle repeats after a regular interval of time. It is not necessarily the to and fro motion since the particle in the circular motion also repeats its original position after a regular interval of time. Thus, the option A is incorrect.
Cyclic motion: It is a circular motion of the particle in which the particle repeats its position after a regular interval of time. Therefore, in the cyclic motion, the particle does not follow the to and fro motion. Thus, the option C is incorrect.
Oscillatory motion: We know that in an oscillatory motion, the particle vibrates back and forth about its mean position. Therefore, we can say that the to and fro motion is the oscillatory motion.

So, the correct answer is option B.

Note: Periodic and cyclic motion also repeats after a regular interval of time but they do not have to and fro motion. The mass attached to a vertical spring oscillates up and down about its mean position and thus said to be an oscillatory motion. The motion of the simple pendulum is a to and fro motion.