JEE Main 2022 · 27 Jul · Shift 1 · Physics Q33

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PhysicsSingle correct+4 / -1Question 33 of 90

Sand is being dropped from a stationary dropper at a rate of 0.5 kgs $^{-1}$ on a conveyor belt moving with a velocity of 5 ms $^{-1}$ . The power needed to keep the belt moving with the same velocity will be :

1.25 W

2.5 W

6.25 W

12.5 W

Answer and worked solution

Official answer: D

Power $=\frac{dm}{dt}v^2=0.5\times25=12.5$ W.

(Half goes into the sand's kinetic energy, half is lost in friction.)

(D)

Topics:Power Variable mass systems

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JEE Main 2022 · 27 Jul · Shift 1, Physics question 33