A staircase contains three steps each 10 cm high and 20 cm wide figure. What should be the minimum horizontal velocity of a bal rolling off the upper most plane so as to hit directly the lowest plane?

Explanation

Formula for this condition is given by `n = (2 h u^2)/(g b^2)`. Where `h` is the height of each step, `b` is the width of step, `u` is the horizontal velocity of projection, and `n` is the number of step.
`rArr 3 = (2 xx 10 xx u^2)/(10 xx 20^2) rArr u^2 = 200 cm s^-1 = 2 ms^-1`.