JEE PYQ: Laws Of Motion Question 21
Question 21 - 2020 | 07 Jan Shift 2] (MCQ)
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 ($g = 10,\text{m/s}^2$) must be at least:
(1) 56300 W
(2) 62360 W
(3) 48000 W
(4) 66000 W [Correct]
Show Answer
Answer: (4)
Solution
$F = (680 + 920) \times 10 + 6000 = 22000$ N. $P = Fv = 22000 \times 3 = 66000$ W.
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