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petern
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[SOLVED] Please Check to See if I'm Doing Work-Energy Problem Correctly
A child riding a bicycle has a total mass of 40 kg. The child approaches the top of a hill that is 10 m high and 100 m long at 5 m/s. If the force of friction between the bicycle and the hill is 20 N, what is the child's velocity at the bottom of the hill?
K = 1/2 * mv^2, U = mgh, W = delta E, W = Fx * cos(theta)
Can someone check to see if I'm doing this correctly. I think what they're trying to say is that you're already at the top.
I would first do K-initial + U-initial = 4420 J. Then Then set that to Fx and solve for F which is 44.2 N. Subtract 20 N from that and you get 24.2 N and multiply it back by x which gives you 242 J. Set that to K-final and solve for v and you get 11 m/s.
Did I do everything correctly?
Homework Statement
A child riding a bicycle has a total mass of 40 kg. The child approaches the top of a hill that is 10 m high and 100 m long at 5 m/s. If the force of friction between the bicycle and the hill is 20 N, what is the child's velocity at the bottom of the hill?
Homework Equations
K = 1/2 * mv^2, U = mgh, W = delta E, W = Fx * cos(theta)
The Attempt at a Solution
Can someone check to see if I'm doing this correctly. I think what they're trying to say is that you're already at the top.
I would first do K-initial + U-initial = 4420 J. Then Then set that to Fx and solve for F which is 44.2 N. Subtract 20 N from that and you get 24.2 N and multiply it back by x which gives you 242 J. Set that to K-final and solve for v and you get 11 m/s.
Did I do everything correctly?
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