Work done by a man in carrying a suitcase weighing 10 kg on his head while walking 5 m horizontally (g=10) is
A. 500 J
B. 250 J
C. 50 J
D. 0 J
Answer: Option D
Solution (By JKSSB Mock Tests)
Force (weight) is vertical (upward to support), displacement horizontal, angle 90°, cos90°=0, work = 0. No work against gravity because vertical height doesn't change. Energy spent is internal muscular effort, but physics work zero.
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