A tennis player serves a ball horizontally, giving it a speedof 24 m/s from a he

Question

A tennis player serves a ball horizontally, giving it a speedof 24 m/s from a height of 2.5m. The player is 12m from the net.The top of the net is 0.90m above the court surface. The ballclears the net and lands on the other side. Air resistance isnegligible. By what distance does the ball clear the net? A tennis player serves a ball horizontally, giving it a speedof 24 m/s from a height of 2.5m. The player is 12m from the net.The top of the net is 0.90m above the court surface. The ballclears the net and lands on the other side. Air resistance isnegligible. By what distance does the ball clear the net?

Explanation / Answer

do you need to know the height of the ball when it passes overthe net, or the distance the ball has traveled past the net? I'll give you both just in case.
Vx = 24 m/s
vertical acceleration is that of gravity, therefore usingV = Vo + at Vy = 0 - 9.81m/s2 (t)
to find the height of the ball when it passes the net, you ned to know the amount of time that has passed. youfind this using the horizontal velocity and the horizontal distanceof the net. when there is no acceleration, x = Vt,therefore t = x / V t = 12m / 24 m/s = .5 s
use this time with the vertical velocity and accelerationwith y = Vot + (1/2)at2 y = 0 +(1/2)(-9.81m/s2)(.5s)2 = -1.23m
this is the vertical distance from starting that it hastraveled, so it is 2.5m - 1.23m above ground, or 1.27m aboveground, or 1.27 - .9m above the net, or .37m above the net


to find the distance the ball has traveled, you need to findthe time it took for the ball to hit the ground, orwhen y = 2.5m y = Vot + (1/2)at2 2.5m = 0 + (1/2)(9.81)t2   => t = .71s
use this time with the horizontal velocity to see how far ittravelled x = Vt = (24m/s)(.71s) = 17.04m
therefore the ball travelled 17.04m - 12m past the net, or15.04m past the net

Hope this was all clear and that it helped!

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