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Homework Statement
A tennis player hits a ball horizontally towards a net of height 0.90 meters, at an initial speed of 25m/s. The ball is hit at a height of 2.5 meters above the ground and at a horizontal distance of 15 meters from the net. Ignore the effects of air resistance and spin
(a) show that the time it takes the ball to reach the net is 0.6 seconds
(b) hence calculate the change in height of the ball during this time
(c) determine the height at which the ball hits the net
Homework Equations
s = vt+1/2gt2
The Attempt at a Solution
(a) sv = vvt + 1/2 gvt2
∴t =√2sv/gv
∴t = 0.7 seconds
but t should = 0.6 seconds
(b) sv = 1/2 gvt2
∴sv = 1/2 x 9.8 x 0.62
∴sv = 1.764 meters
(c)
2.5-1.764 = 0.736 meters
but I know these answers are wrong, since part (a) is wrong. Where am I going wrong?