1.

A ball rolls of the top of a stair way with a horizontal velocity u m s^(-1). If the steps are h metre high and b metre wide, the time taken by the ball to hit the edge of n^(th) step, is

Answer»

`(hu)/(gb)`
`(2hu)/(gb)`
`(2hu^2)/(gb)`
`(hu^2)/(2gb)`

Solution :The BALL reaches `N^(th)` step in time t, then bn = ut or t=bn/u ,
ALSO , `nh=1/2 g t^2 = 1/2 g XX (b^2n^2)/u^2, therefore n=(2u^2H)/(gb^2)`
Time taken to travel vertical distance nh is
`t=sqrt((2nh)/g)=sqrt((2h)/gxx(2u^2h)/(gb^2))=(2uh)/(gb)`


Discussion

No Comment Found

Related InterviewSolutions