An elevator is going upward with constant velocity v_0. One end of light spring of constant k , is fixed to the ceiling of the elevator…

Q: An elevator is going upward with constant velocity v0. One end of light spring of constant k , is fixed to the ceiling of the elevator. A naughty body inside elevator compresses the spring through a compression x0 and in the mean time the elevator moves by a distance s. the work done by the naughty body with respect to ground on the spring is

(a) $ \frac{1}{2} k x_0^2 $

(b) $ \frac{1}{2} k (x_0 + s )^2 $

(c) $ \frac{1}{2} kx_0 s $

(d) Same as that in elevator frame

Ans: (a) , (d)