You can change the initial velocity for both particle with your mouse (drag the RED arrow).

The horizontal velocity for the top one should be larger than the lower one.

The top one will move with constant velocity, while the second will need to move up the hill (with constant deceleration a=-g*sin?)

You can also drag the yellow box to change the height of the slope.

Two traces shows X(t) for both particles. Try to find out the answer from those two curves.

Press the

*** Remember: [color=red]You need to hit [b]ENTER[/b] after you enter the value[/color]. (the box turn yellow if you did not hit ENTER)

I hope you got the correct answer! :)