Question

What kind of motion does the pendulum of a wall-clock exhibit?
(A) Rotatory motion
(B) Circular motion
(C) Linear motion
(D) Oscillatory motion

Answer 1

Hint
A pendulum of a wall clock is suspended from a fixed point. It travels sideways from its equilibrium position as the second progress.

Complete step by step answer
Motion is defined as the change in an object’s position with time. Some objects travel in a straight line like a laser beam, while some move in circular patterns like a Ferris wheel. In mechanics, there are four basic types of motion: rotatory, linear, and oscillatory motion. The rest all are just combinations and variations of these basic types.
Rotatory motion occurs when an object rotates in a circular orbit along a single axis of rotation. For example, the motion of wheels as a car is running on the road is a type of circular motion.
Linear motion happens when the object travels in a straight line. It is also known as rectilinear motion. Examples include an airplane running for take-off on the runway in a straight line.
Oscillatory motion is a particular type of motion. In this, an object has an equilibrium position which it retains while at rest. As the object is brought into motion using an external force, it starts moving to and fro along the mean position. The most common and widely known example of this is the pendulum.
Hence, the pendulum undergoes oscillatory motion, and the answer is (D).

Note
Ideally, if we were to assume a box such that no friction or opposing forces are present in it, the pendulum would be expected to oscillate forever. This is because there would be no drag to or opposing forces to bring the pendulum to a stop, ever.