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ganondorf29
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Homework Statement
The rope of a swing is 2.90 m long. Calculate the angle from the vertical at which a 82.0 kg man must begin to swing in order to have the same KE at the bottom as a 1450 kg car moving at 1.11 m/s (2.48 mph).
Homework Equations
k=(m*v^2) / 2
U = mgh
The Attempt at a Solution
I first found the kinetic energy of the car. 1/2*[(1450)*(1.11^2) = kcar. I found kcar to be 893.273 J. Than I used U=mgh to find the height the man must be to have the same amount of kinetic energy. Kcar = 82*9.8*h. I found the height to be 1.11m. Than I set up a triangle and tried cos^-1 = (1.11/2.9) to find theta. I got 67.5 deg, but that's wrong. Any suggestions?