Question

A block A can slide on a frictionless incline of angle θ and length l, kept inside an elevator going up with uniform velocity v (figure 5−E22). 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 n the body to move sown the plane is F = mg sinθ

Answer 2

given :

The force on the block which makes the body move down the plane is the component of its weight parallel to the inclined surface.

F = mg sinθ

Acceleration, g = sin θ

Initial velocity of block, u = 0

Distance to be covered

s = l

a = g sin θ

Using,

s=ut+1/2at², we get:

l=0+1/2(gsinθ)t²

⇒t²=2l/gsinθ

⇒Time taken, t=√2l/gsinθ