Question

What is the difference between uniform linear motion and uniform circular motion? Explain with examples.

Answer 1

Hint : Uniform circular motion is related to motion along a uniformly circular path. While uniform linear motion is related to motion along a straight line with the same velocity. In uniform circular motion, either magnitude or direction of the velocity changes while in uniform linear motion, magnitude as well as direction remains constant.

Complete step by step solution:

Uniform linear motion	Uniform circular motion
Motion of body in straight line path with constant velocity.	Motion of the object in a circle whose radius is constant with a constant angular velocity.
The motion is not accelerated.	Tangential acceleration is zero so the angular velocity is constant.
The direction of motion doesn’t change. The direction is the same throughout the motion.	Radial acceleration is v2/r (centripetal acceleration) and directed towards the centre.
Ex- A car running on a straight road.	Ex- Motion of earth around the sun.
Ex- Motion of train on track with constant speed.	Ex- Artificial satellites orbiting around the earth.

A car running on a straight road- Let us assume a car which is running on a straight road. During its motion, the car is running with a constant speed and in the same direction. So, the car is moving with the constant velocity and does not have any acceleration. Hence, the motion will be called uniform linear motion.
Motion of earth around the sun- We know that all the plates rotates around the sun. Our earth is one of them. The path in which the earth rotates is circular (nearly). So, there is only one acceleration which is applicable on earth during the motion is radial acceleration or centripetal acceleration. Tangential acceleration is zero here. So, the velocity is constant here as either magnitude of velocity changes or the direction of the velocity changes. The resultant always remains the same or constant. Hence, the motion is uniform circular motion.

Additional Information: Motion is one of the most common events in our daily lives. For example, a moving car, a child running on the road or a fly in the air, are all said to be in motion. Therefore, in general terms, a body is said to be in motion if it changes its position with respect to the reference point and time. Depending on the path taken by the particle, the speed can be of various types such as projectile motion, rectangular motion, rotational speed, etc. For now, we will only focus on rectilinear motion which is also known as linear motion.

Note: Uniform circular motion can be described as the motion of an object in a circle at a constant speed. As an object moves in a circle, it is constantly changing its direction. An object undergoing uniform circular motion is moving with a constant speed. However, it is gaining momentum due to a change in its direction.