Question

5. A rocket with mass 40 kg is filled with fuel of mass 360 kg. Exhaust velocity
of gases is 2 km/sec. Find the final velocity attained by the rocket?​

Answer 1

Answer:

Velocity of rocket is given as

v=uln

M−rt

M

where M is the Total mass of rocket and fuel at t=0 second

That is,

M=20+180=200kg

and

Rate of consumption of fuel, r=2kg/sec

Velocity of gas rejection with respect to rocket, u=1.6km/sec

Ultimate velocity is achieved when all the fuel

burns,

That is,

M−rt=20kg

So,

v=1.6ln

20

180

=3.515km/sec