An electron is moving in a circle of radius 2m with speed of 4 m/s. Find the acceleration of the electron.

The particle of mass $$m$$ is moving in a circular path of constant radius $$r$$ such that its centripetal acceleration $$a_c$$ is varying with time $$t$$ as $$a_c=k^2 r t^2$$, where $$k$$ is a constant. The power delivered to particle by the forces acting on it is

Assertion : For looping a vertical loop of radius, $$r$$ the minimum velocity at lowest point should be $$\sqrt{5 g r}$$.

Reason : In this event the velocity at the highest point will be zero.