Galileo threw a large rock upward from a tower balcony at an angle of 25.0o above the horizontal with an initial speed of 15 m/s. If the rock hits the ground 3.0 s later, how high above ground was the rock when it left Galileo’s hand?

Answer 1

figure the vertical component of initial veloctiy: 15sin25

then

hf=hi+Viv*t-4.9t^2 hf=0, solve for Hi.

I am wondering how Galileo measured time? Stopwatch? How did he measure intial veloctiy?