The upper half of an inclined plane with inclination `phi` is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coefficient of friction for the lower half is given by

Options

A. `mu =2 tan theta`
B. `mu =(2)/(tan theta)`
C. `mu = tan theta`
D. `mu =(1)/(tan theta)`

Answer

A

Explanation

`V_(rough) =sqrt(2gl(sintheta-mu_(k)costheta))`
`V_("smooth") =sqrt(2glsintheta)`