Physics problem, Tennis ball? easy question, though need advice?

Question

A tennis player serves a ball horizontally. What minimum speed is required for the ball to clear the 0.90m high net about 15.0 from the server if the ball was launched from a height 2.5m above the ground? where will the ball land if it just clears the net? How long in the air assuming air resistance is negligible?

What I did so far was subtract the height of the net from the height of the person. So i get

x0 = y0 = 0

x = 15

y = -1.6

ax= 0

ay= -9.8

vy0= 0

vx0= ??

t= ??

should i just treat it as if its a ball off a cliff now? and what about the second part...thank you

Answer 1

Shouldn't you ask it in Physics section?

The problem boils down to this: The time to reach .90 m for a free-falling body starting at rest from a height of 2.5m should be equal to the time taken to traverse 15m at that speed. The time to reach the ground should be calculated (same as before). How long does the ball travel during this time at the speed calculated above?