physics
posted by anonymous on .
A place kicker must kick a football from a point 36.0 meters (about 40yds)from the goal. as a result of the kick, the ball must clear the crossbar, which is 3.05 meters high. When kicked the ball leaves the ground with a speed of 20.0 m/s at and angle of 53 degrees to the horizontal
a) how much does the ball clear or fall short of clearing the crossbar
b) does the ball approach the crossbar while still rising or while falling?

hf=hi+ViSintheta*t1/2 g t^2 in the vertical.
in the horizontal,
36=vi*cosTheta*t solve for t in terms of theta.
t=36/(vi*cosTheta)
Now put that into the other equation above.
hf=0+Visintheta*36/vicosTheta1/2 g 36^2/Vi^2cos^2 theta
You know Vi, Theta, solve for hf. 
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