Question

A particle of mass m is describing a circular path of radius r with uniform speed. If L is the angular momentum of the particle about the axis of the circle, the kinetic energy of the particle is given by

• A. $L^{2}/mr^{2}$
• B. $L^{2}/2mr^{2}$
• C. $2L^{2}/mr^{2}$
• D. $mr^{2}L$

Answer 1

Answer: (B)

$L^{2}/2mr^{2}$

Answer 2

Rotational kinetic energy $E = \frac{L^{2}}{2I} = \frac{L^{2}}{2mr^{2}}$

(As for a particle $I = mr^{2}$)