Question

A ball is rolling on the top of a stair with a horizontal velocity U metre per second if the steps RH metre high and demons hide the ball will hit the age of nth step if

Answer 1

Horizontal distance covered by ball =nb

Vertical distance covered by ball =nh

If the time taken to hit the edge of nth step is t, then

nb=utnb=ut

nh=12nh=1/2gt^2

Eliminating t, we get,

nh=12nh=1/2*g(nb/u)^2

n=2hu^2/gb^2




hope it helps...