A tennis player serves a tennis ball it is moving horizontally when it leaves the racquet. When the ball travels a horizontal distance of 12 meters, it has dropped 55cm from its original height when it left the racquet. What is the initial speed of the ball?

Answer 1

d = 0.5g*t^2 = 0.55 m.
4.9t^2 = 0.55.
t^2 = =.112.
t = 0.335 s. = Fall time.

Dx = Xo * t = 12 m.
Xo * 0.335 = 12.
Xo = 35.8 m/s.