In a rocket,fuel burns at the rate of $2 \, kg/s$. This fuel is ejected from the rocket with a velocity of $80 \, km/s$. The force exerted on the rocket is ............. $N$.

$A$ block of metal weighing $2 \,kg$ is resting on a frictionless plane (as shown in figure). It is struck by a jet releasing water at a rate of $1 \,kg \,s^{-1}$ and at a speed of $10 \,m \,s^{-1}$. Then,the initial acceleration of the block,in $m \,s^{-2}$,will be:

$A$ rocket of initial mass $6000 \ kg$ ejects gases at a constant rate of $16 \ kg/s$ with a constant relative speed of $11 \ km/s$ in gravity-free space. What is the acceleration of the rocket $1 \ min$ after the blast? (in $m/s^2$)

The rate of fuel consumption in a rocket is $40 \ kg/s$. The velocity of the exhaust gases coming out of the rocket is $5 \times 10^4 \ m/s$. What is the thrust force acting on the rocket?

Is the formula $\vec{F} = m\vec{a}$ valid in all circumstances? Why?

If the force on a rocket having an exhaust velocity of $300 \, m/s$ is $210 \, N$,then the rate of combustion of the fuel is ........... $kg/s$.