Ball and Ramp: Solving for Time and Evaluating Position

[atomB]

This is from a practice exam without an answer key. I tried the problem once before and am getting a different solution now. My method is solving for the time t when the x position is the width of ramp, and then evaluating y(t) to see if it is more or less than the height of the ramp.

The problem statement, relevant equations, and attempt are in the image.

 

[Simon Bridge]

That sounds like a reasonable method - what did you do before?

 

[haruspex]

There is something missing from your equation for y(t)