Projectile motion of a rolling ball

[lolimcool]

Homework Statement

a ball rolls off the top of a stairway with a horizontal velocity of magnitude 1.50m/s. The steps are 20cm high and 20 cm wide. Which step will the ball hit first?

Homework Equations

d = v1t + at^2
a = -9.8m/s^2
t= 2viSinθ/ 9.8
horizontal displacement = vi^2Sin2θ/ 9.8

The Attempt at a Solution

i actually have no idea what I am doing

 

[rl.bhat]

Hi lolimcool, welcome to PF.
The step has equal height and width.
So the ball will hit the place where h and x are the same.
Write down the expression for x and h. Solve for t. Then find step where he ball hits.