Question

A satellite moves around the earth in a circular orbit with constant speed. Explain is the motion uniform or accelerated?

Answer 1

In order to solve this question, we should know that any object which moves in a circular path is affected by some force called centripetal force and whenever there is change in velocity of a body, it’s said to be accelerated motion. Here we will discuss the motion of satellites in circular orbit with constant speed.

Complete step by step answer:
When a satellite moves in a circular orbit around the earth with constant speed, it has a constant magnitude of speed but the direction of the velocity changes continuously at every instant of motion and change in velocity is no more a uniform motion but an accelerated motion.
The motion of a satellite in circular orbit with changing direction of velocity and the centripetal force acting towards the centre of the circular path is shown in the diagram as

So, in circular motion, the direction of velocity keeps changing at every instant of path and acceleration acts on the body due to centripetal force and acceleration a due to velocity v and radius r of the satellite path is $a = \dfrac{{{v^2}}}{r}.$
Hence, the motion of satellites around the earth in circular orbit is accelerated one.

Note: It should be remembered that the actual path of satellites around the earth and of earth around the sun are elliptical but for rough calculations we assumed the path of satellites and planet as circular. Also, speed is a scalar quantity while velocity is a vector quantity having magnitude as well as direction.