- #1
Jshumate
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Homework Statement
Near the surface of the Earth, a block of cheese with mass m lies on the foor of
a elevator cab with mass M = 1,000m (i.e., the mass of the cab is 1,000 times
the mass of the cheese) that is being pulled upward by a cable. If through the
distance d = 2m, the normal force on the block from the floor has constant
magnitude FN = 3N, how much work is done on the cab by the force from the
cable?
Homework Equations
W = fd
F = ma
The Attempt at a Solution
The distance moved is two meters, so the only unknown necessary to solve is the force from the cable on the cab.
If you consider the entire system of cheese and elevator,
Fc - mg - 1000mg = 1001ma
Just the cheese,
3 - mg = ma
a = 3/m - g
Combine the two,
Fc = 1001mg + 1001m(3/m - g)
Fc = 1001mg + 3003 - 1001mg
Fc = 3003 N
W = (3003N)(2m) = 6,006 J
However, the answer is apparently 6,001 J. Can anyone explain why to me? Or is this a misprint on the answer sheet...