A cannon is fired from a cliff top 15m high and at 30 degrees. It takes 3 seconds for canon to reach the earth, what is the initial velocity of the cannon

Answer 1

h = (Vo*sin(-30))*(t) + 0.5g*t^2=15 m.
(Vo*sin(-30))*(3) + 4.9*3^2 = 15
-1.5Vo + 44.1 = 15
-1.5Vo = 15-44.1 = -29.1
Vo = 19.4 m/s.