Question

An object of mass 0.01 kg is moving in a circular path of radius 150 cm. if it takes 3 sec to make one complete revolution. calculate the magnitude and the direction of the centripetal force.

Answer 1

The centripetal force will be

$$F=m\frac{v^2}{R}=m\frac{(2\pi R/T)^2}{R}=\frac{4m\pi^2R}{T},\\\space\\ F=\frac{4\cdot0.01\pi^2\cdot1.5}{3}=0.20\text{ N}.$$

The force is directed into the center of the circle perpendicularly to the object's velocity.