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kisha
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Homework Statement
A tennis player serves in a match.He hits the tennis ball so that it flies off the racket with a velocity of 50m/s at 10° to the horizontal.
Sx=11m
Sy=2.4 - 1.07 = 1.33m
ux=50cos10°
uy=50sin10°
time=?
a)Show that the ball cannot pass over the net.
b)The player serves again.He hits the ball at the same height.The ball flies off at the same speed but it only makes an angle of 5° with the horizontal.
(i)Show that the ball passes over the net this time.
(ii)When does the ball land after the serve?Find its horizontal displacement when it lands.
(iii)Find the velocity at which the ball hits the floor.
Homework Equations
Vy = Uy - gt
Sy=Uy - 1/2gt^2
Sx=Ux(t)
Vx=Ux
The Attempt at a Solution
Time of flight=[PLAIN]http://img600.imageshack.us/img600/5889/29072134.png
vertical distance = h = usinθ(t)-1/2gt^2
=[PLAIN]http://img825.imageshack.us/img825/369/24954548.png
=[PLAIN]http://img202.imageshack.us/img202/5079/78644637.png
Since,
Sy=Sxtanθ
h=[PLAIN]http://img191.imageshack.us/img191/6696/36239012.png
Therefore,the ball passes below the net at a separation of=
[PLAIN]http://img576.imageshack.us/img576/6231/89145724.png
In other words,it is impossible for the ball pass the net.
Can anyone help with this?How to prove the ball cannot pass over the net?
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