Part 2 of theoretical portion of physics lab I got the formu

Part 2 of theoretical portion of physics lab.

I got the formulas for part 1 as you can see in the pictures but I am stuck on Part 2 at the moment.

H = 0*t +0.5*gt², where g = 9.8 m/s²
therefore t from equation 1 is sqrt(2H/g) sec
so R = V*t
therefore V = R/sqrt(2H/g)

Note that here since horizontal axis does not have any acceleration therefore the velocity will not change in the system