Rita and Sameer each lift identical school bags of mass from the ground to the same…

PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy

Problem

Rita and Sameer each lift identical school bags of mass 15 kg15\,\text{kg} from the ground to the same shelf 1.5 m1.5\,\text{m} high. Rita completes the task in 2 s2\,\text{s}, while Sameer takes 3 s3\,\text{s}. A third student, Karan, lifts a lighter bag of mass 10 kg10\,\text{kg} to the same shelf in 1.5 s1.5\,\text{s}. Use this information to answer the following parts. (i) Explain what is meant by the power developed by a person in this situation. (ii) Without performing any numerical calculation, arrange Rita, Sameer, and Karan in the order of decreasing power and justify your answer qualitatively. (iii) If the height of the shelf were doubled for all three students while their times remained unchanged, would your answer to part (ii) change? Give reasons for your choice.

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