# What is circular motion? (with pictures)

Uniform circular motion can be seen in a Ferris wheel.

In the field of physics, circular motion is a term that defines the movement of an object in a rotational manner. In this motion, an object travels around in a circle, like the planets that move around the Sun in each of their orbits. The object also moves around its center an equal distance, but accelerates as it rotates to maintain circular motion.

A roller coast is an example of non-uniform motion.

An important element that makes circular motion possible is an inward force; this is also called centripetal force. According to Newton’s Law of Motion, an object generally requires a certain force to act on it in order for it to move, accelerate, and react. In circular motion, the absence of centripetal force will cause the object to move only in a straight line, as there is nothing pushing the object inwards. For example, a stone tied to a rope can be swung continuously because the rope pulls the stone towards the center. The boulder drops straight to the ground, however, when the rope is cut.

A circular motion has two types: uniform and non-uniform. In uniform motion, the object travels at a constant speed. This does not take into account the velocity of the object, which is the change in speed or direction, as a rotating object is always changing direction.

Non-uniform circular motion, on the other hand, causes an object to move at varying speeds. The distance between the object and the center of the sphere also changes. The object’s speed will increase if the distance is smaller, while a greater distance slows down the object’s rotation. For example, the stone attached to the rope will spin faster if the rope is shorter, but it will spin slower if the rope is longer. This is because the force acting on the object becomes weaker or stronger when the distance is greater or less, respectively.