June stands on the roof of the house which is 22.8 m high and she throws the ball at an initial speed of 4.90 m/s downward at Ben who is 1.80m tall. a) With what speed does she hit her target's head and b) how much time was it in the air? Displacement= 21 m.
-Place coordinates on roof
a. V^2 = Vo^2 + 2g*d
V^2 = 4.9^2 + 19.6*21 = 435.61
V = 20.87 m/s.
b. V = Vo + g*t
t = (V-Vo)/g = (20.87-4.9)/9.8 = 1.63 s.