Question

If the force on a rocket moving with a velocity of $300m/s$ is $210N$, then the rate of combustion of the fuel is (in kg/s)

• A. $0.8$
• B. $0.7$
• C. $0.6$
• D. $0.3$

Answer 1

The correct option is B $0.7$

Force acting on the rocket $F=210N$

Its velocity $v=300m/s$

Thus rate of fuel consumption $\frac{dm}{dt}=\frac{F}{v}$

$\therefore$ $\frac{dm}{dt}=\frac{210}{300}=0.7$ $kg/s$