question_answer

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

A)  127.5 \[kg\text{-}{{s}^{-1}}\]      

B)         137.5 \[kg\text{-}{{s}^{-1}}\]

C)  185.5 \[kg\text{-}{{s}^{-1}}\]      

D)         187.5 \[kg\text{-}{{s}^{-1}}\]