Question

You want to figure out how fast you can throw a ball, but don't have access to a radar gun. You measure the height from the ground to your hand as you throw and discover that when you throw a ball it leaves your hand at a height of 2 m from the ground. You then throw a ball horizontally and discover that it hits the ground 20 m from where you're standing. How fast in m/s did you throw the ball?

Answer 1

h=gt²/2=>
t=sqrt(2h/g).

s=vt=>
v=s/t=s/ sqrt(2h/g)=
=20/sqrt(2•2/9.8)=31.3 m/s