Children sled down a 43 -long hill inclined at 24 . At the bottom, the slope levels out.
1 Answer
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PE(initial) = mgh = mgLsinθ = mg43sin24* = 17.49mg J
W(friction) = f(friction) x L = µ x N x L = µ x mgcosθ x L = 0.1 x mgcos24* x 43 = 3.93mg J
=>By the law of energy conservation:-
=>KE(final) = PE(final) - W(friction)
=>KE(final) = 17.49mg - 3.93mg = 13.56mg J
=>Let children travel s meter on the level, By work energy relation at level:-
=>W(friction) = ∆KE
=>F(friction) x s = ∆KE
=>µ x mg x s = 13.56mg
=>s = 13.56/0.12
=>s = 113 m