Question

Which type of motion of an object that moves at a fixed distance from a fixed point?
A) Periodic motion
B) Rectilinear motion
C) Circular motion
D) None of the above

Answer 1

Hint : A type of motion when the object moves at a fixed distance from a fixed point must be such that the displacement of the object from the fixed point must remain constant at all times of its motion. So from the options given in the question we need to see which of these motions has a constant displacement from a point at all times.

Complete step by step answer
In option (A), for a periodic motion, the object oscillates about a fixed point i.e. to and fro from the fixed point. But the displacement of the object from the fixed-point changes with time and is not constant so option (A) is not the correct choice.
In option (B), rectilinear motion is a kind of motion where the object travels in a straight line with a constant velocity so the object is continually being displaced and does not lie at a fixed distance from any point.
In option (C), for a circular motion, the object travels in a circle about a fixed point. Since all the points of a circle lie at a fixed distance from a fixed point, we can say that the object moves at a fixed distance, which is equal to the radius of the circle from a fixed point that is the centre of the circle.
Hence option (C) is the correct choice.

Note
Circular motion can be observed in many day-to-day phenomena like the motion of a clock hand, a gear turning inside a gear head, and so on. In all of these examples, the object travels in a circular motion about a fixed point. The trajectory of the object in such cases will be along the circumference of its circular motion.