$A$ balloon has a mass of $10\,g$ in air. The air escapes from the balloon at a uniform rate with a velocity of $4.5\,cm/s$. If the balloon shrinks completely in $5\,s$,then the average force acting on the balloon will be (in $dyne$).

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?

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

$A$ rocket with an initial mass $m_0$ is going up with a constant acceleration $a$ by exhausting gases with a velocity $v$ relative to the rocket motion. The mass of the rocket at any instant of time $t$ is (assume that no other forces act on it).

$A$ satellite in force-free space sweeps stationary interplanetary dust at a rate $\frac{dM}{dt} = \alpha v$,where $M$ is the mass,$v$ is the velocity of the satellite,and $\alpha$ is a constant. What is the deceleration of the satellite?

$A$ rocket has a mass of $100 \, kg$. $90\%$ of this is fuel. It ejects fuel vapours at the rate of $1 \, kg/s$ with a velocity of $500 \, m/s$ relative to the rocket. It is assumed that the rocket is outside the gravitational field. The initial upthrust on the rocket when it just starts moving upwards is ......... $N$.