Question

A block A can slide on a frictionless incline of angle $\theta$ and length l, kept inside an elevator going up with uniform velocity v in figure. Find the time taken by the block to slide down the length of the incline if it is released from the top of the incline.

Answer 1

The driving force on the block which makes the body to move down the plane is,

$F-mgsin\theta$

$\therefore$ Acceleration =$gsin\theta$

Initial velocity of block, u = 0

S = l

a= g $sin\theta$

Now, $S=ut+\frac{1}{2}a{t}^2$

$\Rightarrow l=0+\frac{1}{2}\left(gsin\theta \right)t^2$

$\Rightarrow t^2=\frac{2l}{gsin\theta }$

$\Rightarrow$ Time taken , t = $\frac{2l}{gsin\theta }$