A body is projected up along the rough inclined plane from the bottom with some velocity. It travels up the incline and then returns back. If the time of ascent is `t_(a)` and time of descent is `t_(d)` then

Options

A. `t_(a)=t_(d)`
B. `t_(a)gtt_(b)`
C. `t_(a)ltt_(d)`
D. data insufficient

Answer

C

Explanation

Let velocity of projection be V and velocity of the block when it returns back=V'
then VgtV' (since some K.E. is lost to friction)
Hence average velocity during ascent gt average velocity during descent
`rArr t_(a) lt t_(d)`