91Ó°ÊÓ

If an object moves on a circular path, the motion is known as circular motion.The object has a tangential velocity whose direction is perpendicular to the centripetal acceleration, causing it to move in the circular path. For example, a car rounds the corner in a curve path at a constant speed.

Suppose a brick is tied at the rope’s end and whirled around in a circular motion in a horizontal plane. The brick will have a velocity vector always tangential to the circular path, a centripetal force due to the tension in the string towards the center, and the force of gravity in the downward direction.

In a circular motion, if the object is released, it will undergo projectile motion along the path tangential to the circular path, at the time of release. The reason behind this is that the centripetal force responsible for circular motion vanishes at the time of release. Thus, the circular motion also vanishes but the gravitational pull of the earth is still acting on the body and the body undergoes projectile motion.

Figure: The projectile motion of the particle after release.

Here,$\stackrel{→}{\mathrm{a}}$ is the acceleration due to gravity.