A 3.0-kg mass is dropped from the edge of a 50-m tall building with an initial speed of zero. The mass strikes the ground with a downward velocity of 25 m/s. Find the change in mechanical energy of the mass caused by air resistance between the point where it is dropped and the point where it strikes the ground.
A. ?0.46 kJ
B. ?0.53 kJ
C. ?0.61 kJ
D. ?0.38 kJ
E. ?0.81 kJ
Answer: B
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