A rolling body is connected with a trolley car by a spring of stiffness `k`. It does not slide and remains in equilibrium relative to the acceleration trolley car. If the trolly car is stopped after a time `t=t_(0)`. (the rolling body touches the trolly)

Options

A. `tau_(C)ne0` for `ctltt_(0)`
B. `f=0` for `tltt_(0)`
C. `x=(ma)/k`, where `x`=deformation of the spring
D. `(KE)_(max)=1/2ma^(2)t_(0)^(2)`, where`(KE)_(max)` is the maximum `KE` of the rolling body

Answer

B

Explanation

`f=0` for `tgtt_(0)` until it can stop no friction acts because it neither slides nor rotates due to action of the rolling