Physicsmedium · Past Paper
A machine of efficiency 80% is used to lift a 100 N load through 2 m. The work input is:
A200 J
B250 J
C160 J
D80 J
✓ Correct Answer: B — 250 J
Work Output = 100 * 2 = 200 J. Input = Output / Efficiency = 200 / 0.8 = 250 J.
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