The motion of a rocket in an upward direction with high speed is based on the principle of conservation of:

Sand is being dropped on a conveyor belt at the rate of $2\,kg/s$. The force necessary to keep the belt moving with a constant speed of $3\,m/s$ will be ........... $N$.

In a rocket of mass $1000\, kg$,fuel is consumed at a rate of $40\, kg/s$. The velocity of the gases ejected from the rocket is $5 \times 10^4\, m/s$. The thrust on the rocket is:

$A$ rocket is fired vertically from the ground with a resultant vertical acceleration of $10 \,m/s^2$. The fuel is exhausted in $1 \,min$ and it continues to move up. What is the maximum height reached (in $\,km$)?

$A$ $600\; kg$ rocket is set for a vertical firing. If the exhaust speed is $1000\; m/s$,the mass of the gas ejected per second (in $kg/s$) to supply the thrust needed to overcome the weight of the rocket is

$A$ cart loaded with sand is moving with velocity $v$. Sand is falling through a hole as shown in the diagram. After falling on the ground,the sand is: