Q 11-05-131JEE MainJEE Main 2022 (27 Jul, Shift 1)Medium
Sand is being dropped from a stationary dropper at a rate of $0.5\ \text{kg s}^{-1}$ on a conveyor belt moving with a velocity of $5\ \text{m s}^{-1}$. The power needed to keep belt moving with the same velocity will be
Answer: (D) $12.5$ W
The belt must supply momentum to the sand at the rate
$$F = v\frac{dm}{dt} = 5\times0.5 = 2.5\ \text{N}$$
$$P = Fv = 2.5\times5 = 12.5\ \text{W}$$
Solution by Sreeraj P, M.Sc Physics