Nathan hits a tennis ball straight up into the air from a height of 1.25m above the ground.
The ball hits the ground after 2.5 seconds.
-Find: the speed with which Nathan hits the ball.
The answer is u=12 ms^-1
Here is how I did it (And it is wrong ...):
u= u m/s
v = 0 m/s
a = -10m/s^2 ; (taking up as +ve).
t=2.5 s
So:
v=u+at ---> 0 = u + -25 ---> u = 25 m/s but this is not the correct answer.
