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Unformatted text preview: mg(Lsin ) = (1/2)mv 2 + (1/2)I 2 mgLsin = (1/2)m(r 2 2 ) + (1/2)(2/5)mr 2 2 = (7/10)mr 2 2 = (10gLsin /7r 2 ) = 61.3 m/s b) The roofs edge is at height H = 4.00 m. How far horizontally from the roofs edge does the ball hit the level ground? The speed of the ball at the edge of the roof is v = r = 4.91 m/s At the edge, the ball is moving at an angle of 35 below the horizontal. x and y components of the intial velocity of the projectile motion is v 0x = v =cos(-35) = 4.02 m/s, v 0y = v sin(-35) = -2.81 m/s When the ball hits the ground, the vertical displacement of the ball is H. The flight time is -H = v 0y t (1/2)gt 2 t = (-v 0y + (v 0y 2 + 2gH))/g = 0.661 s During this time interval, the horizontal displacement of the ball is x = v 0x t = 2.65 m...
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This note was uploaded on 01/25/2011 for the course PHY 2048 taught by Professor Field during the Summer '08 term at University of Florida.
- Summer '08