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taken from BR Physics Ch 3 III.11
So it's your standard slide problem. The question asks: "suppose that as a child slides down the slide we take air resistance into account. The work done by the child on the air is equivalent to the change in:
A. KE
B. PE
C. KE + dPE
D. KE - dPE
So, Ei + W on sys = Ef
W on sys = -W by sys
Ei = PE
Ef = KE
Therefore, W by sys = PE - KE
But the book's answer is C. What am i doing wrong?
So it's your standard slide problem. The question asks: "suppose that as a child slides down the slide we take air resistance into account. The work done by the child on the air is equivalent to the change in:
A. KE
B. PE
C. KE + dPE
D. KE - dPE
So, Ei + W on sys = Ef
W on sys = -W by sys
Ei = PE
Ef = KE
Therefore, W by sys = PE - KE
But the book's answer is C. What am i doing wrong?