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fluffy91
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Homework Statement
A 4kg Ball and a 3kg block of wood were placed in an arrangement as shown below. When the ball was released it fell through the distance of 5m pulling the block of wood up the ramp. If the pulleys were well oiled and the surface of the ramp exerts a frictional force of 2N. What is the final speed of the sphere after falling through the 5m?
Homework Equations
E=MGH
work done= Distance moved x force
1/2mv² =K.E
The Attempt at a Solution
P.E= MGH = 4x10x5 =200 J
energy used to raised the block = 3x3x10+ (2x4) =98J
K.E of sphere after 5 m fall = 200-98 =102J
1/2mv² =102J
V=7.14m/s
But then answer is 5.34m/s
How to solve tis question. I have attached the diagram below
http://img400.imageshack.us/img400/3519/77494753vj1.jpg [Broken]
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