A 50kg man with a 20kg load on his head climbs up 20 steps of 0.25m height each. The work done in climbing is?
Correct answer: C. 3430 J
- A. 100 J
- B. 350 J
- C. 3430 J
- D. 5J
Explanation
The work done in climbing up the stairs is against gravity, therefore the work done is stored as potential energy, soWork = mghwhere m = mass = 50 + 20 = 70 kgand g = gravitational accelaration = 9.8 m/s2and h = 20 x 0.25 = 5 mW = 70 x 9.8 x 5 = 3430 J
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About Work
Work is done when a force produces displacement, with its value determined by the component of force along the displacement. The topic covers positive, negative and zero work, work by variable forces from force-displacement graphs, and the connection between net work and change in kinetic energy.
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