A $5000\ kg$ rocket is set for vertical firing. The exhaust speed is $800\ ms^{- 1}$. To give an initial upward acceleration of $20\ ms^{- 2}$ the amount of gas ejected per second to supply the needed thrust will be $(g = 10\ ms^{- 2})$

Question

Dr. Abubacker · Accepted Answer

(b) $F = \frac{udm}{dt} = m(g + a)$
$\Rightarrow \frac{dm}{dt} = \frac{m(g + a)}{u} = \frac{5000 	imes (10 + 20)}{800} = 187.5\ kg/s$

Q. A $5000\ kg$ rocket is set for vertical firing. The exhaust speed is $800\ ms^{- 1}$. To give an initial upward acceleration of $20\ ms^{- 2}$ the amount of gas ejected per second to supply the needed thrust will be $(g = 10\ ms^{- 2})$

Explanation

Reviewed by Dr. Abubacker

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