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The initial mass of rocket is 1000 kg.Calculate at what rate the fuel should be burnt so that the rocket is given an acceleration of 20 ms-2. The gases come out at a relative speed of \left [ Use\, g= 10\, m/s^{2} \right ]
Option: 1 10\, Kg\, s^{-1}
Option: 2 60\, Kg\, s^{-1}
Option: 3 500\, Kg\, s^{-1}
Option: 4 6\cdot 0\times 10^{2}Kg\, s^{-1}

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M_{initial}= 1000kg
a= 20\, \frac{m}{s^{2}}
V_{rel}= 500\, \frac{m}{s}

F-mg= ma
V_{rel}\frac{dm}{dt}-mg= ma
\left ( 500 \right )\frac{dm}{dt}-1000\times 10= 1000\left ( 20 \right )
500\left ( \frac{dm}{dt} \right )= 1000\left ( 30 \right )
\Rightarrow\left ( \frac{dm}{dt} \right )= 60\left ( \frac{kg}{s} \right )
 

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vishal kumar

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