Question

The motion described by the needle of sewing machine is oscillatory motion.
A. True
B. False

Answer 1

Hint: The oscillatory motion of a body is a kind of motion in which the given body moves to and fro about the same point and after equal intervals of time. The motion keeps repeating itself moving about the same mean position of the body.

Detailed step by step solution:
The oscillatory motion of a body can be differentiated from other types of motion on the basis of the fact that the body executing this motion moves to and fro about a mean point. The body repeats the same to and fro motion regularly at equal intervals of time. This type of motion can be observed in the motion of a simple pendulum.
The motion of the needle of a sewing is oscillatory in nature because the needle it moving about its rest position and mean position in a to and fro motion. The amplitude of motion or the extent to which the needle moves is same every time the to and fro motion takes place.
Hence, the given statement is correct and option A must be chosen by the student.
Additional information:
Periodic motion: A body is said to be executing a periodic motion if the motion repeats itself after a fixed interval of time. For example: The motion of planets around sun is periodic in nature.
Vibrational motion: A body is said to be executing vibrational motion if its moving about its mean position at a very fast rate. For example: When a spring is plucked, it executes vibratory motion.

Note: The student must remember the difference between oscillatory, periodic and vibrational motion. The oscillatory motion is obtained when a body’s motion has characteristics of periodic motion and very slow vibrational motion.