The mass of a rocketis 500 kg and the relative velocity of gases ejecting from it is 250 `ms^(-1)` with respectto the rocket. Find the rate of burning of the fuel to give the rocket an initial aceeleration of 20 `ms^(-2)` in the vertically upward direction. (Take g = 10 `ms^(-2)` )

Options

A. 300 kg `s^(-1)`
B. 60kg `s^(-1)`
C. 90 kg `s^(-1)`
D. 30 kg `s^(-1)`

Answer

B

Explanation

Here m = 500 kg, u = `250 ms^(-1), a= 20 ms^(-2), g = 10 ms^(-2)`
Thrust required, m (a+ g) =`u(dm)/(dt) , (dm)/(dt)=60kg//s`