A rocket consumes 20 kg fuel per second. The exhaust gases escape at a speed of 1000 ms^–1 relative to the rocket. Calculate the upthrust received by the rocket. Also calculate the velocity acquired. When its mass is 1/100 of the initial mass.

According to the problem the rocket consumes the fuel of 20 kg

The speed of the exhausting rate of gas is 1000 m/s

Now, dm/dt=20kg/s  

u=1000m/s  

So, the upthrust on the rocket will be $=\mathrm{u}(\mathrm{dm}/\mathrm{dt})=1000 \mathrm{x} 20= 20000 \mathrm{N}$

For velocity we know, $v=\text{uln }\left[\frac{m_o}{m}\right]$

When the mass is 1/100th of the initial mass of rocket.

The velocity $\mathrm{v}=1000 \mathrm{x} \ln 100=4.6\mathrm{x}{10}^3 \mathrm{m}/\mathrm{s}$