Question:
An elevator in a building can carry a maximum of 10 persons, with the average mass of each person being 68 kg, The mass of the elevator itself is 920 kg and it moves with a constant speed of 3 m/s. The frictional force opposing the motion is 6000 N. If the elevator is moving up with its full capacity, the power delivered by the motor to the elevator (g = 10 m/s2) must be at least :
An elevator in a building can carry a maximum of 10 persons, with the average mass of each person being 68 kg, The mass of the elevator itself is 920 kg and it moves with a constant speed of 3 m/s. The frictional force opposing the motion is 6000 N. If the elevator is moving up with its full capacity, the power delivered by the motor to the elevator (g = 10 m/s2) must be at least :
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At constant speed the motor force equals weight plus friction; power \(=F\,v\).
Updated On: Oct 31, 2026
- 48000 W
- 62360 W
- 56300 W
- 66000 W
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The Correct Option is D
Solution and Explanation
Step 1: Total mass \(=10\times68+920=1600\) kg, so weight \(=1600\times10=16000\) N.
Step 2: Motor force at constant speed \(=16000+6000=22000\) N.
Step 3: \(P=Fv=22000\times3=66000\) W.
Answer: (D) 66000 W
Step 2: Motor force at constant speed \(=16000+6000=22000\) N.
Step 3: \(P=Fv=22000\times3=66000\) W.
Answer: (D) 66000 W
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