Both A 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time. The power expended in raising the 50-kg sack is

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Quizplus · Accepted Answer

The power expended is the same in both cases because power is the rate of doing work, and work is defined as force times distance. For both sacks, the work done is the product of their weight (mass times gravity) and the height they are lifted. Since the 50-kg sack is twice as heavy but lifted half the distance compared to the 25-kg sack, the work done (and thus the power, assuming they're lifted in the same amount of time) is the same.

Both a 50-Kg Sack Is Lifted 2 Meters from the Ground