Question

A tennis player serves a ball horizontally from the service line at a height of 2.50 m.

a. What is the minimum speed required for the ball to clear the net? The net is 0.90 m tall and the distance from the net to the service line is 15.0 m. b. Where will the ball land if it does just clear the net?

c. By how much will the ball clear the net if it is served horizontally and lands 7.00 m beyond the net (22.0 m from the service line)?

Answer 1

Solution,

A)

Motion along vertical direction,

Y = yo + 0.5 gt^2

2.5 = 0.9 + 0.5 x 9.8 x t^2

Time, t = 0.57 sec

Velocity = distance to be covered m time it would take

u = 15/ 0.57 = 26.316 m/s

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b) agiain considering motion along vertical

2.5 = 0.5 *9.8*T^2

T = 0.714 m/s

Horizontal distnace travelled measured from net

R = 0.714 * 26.316 - 15 = 3.797 m

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c)

Total horizontal distance = 7+15= 22 m

Motion along horizontal

22 = uT

u = 22/0.714= 30.18

Time taken by the ball to reach net

t' = 15/ 30.18 = 0.497 s

Considering motion along vertical

h = 0.5 *9.8*0.497-0.9

h = 0.31 m

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