Question

A rocket consumes 20 kg fuel per second. The exhaust gases escape at a speed of
1000 ms- 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.
1) 2 x 104N; 4.6 Km/s
2) 2 x 106N;5.3 Km/s
3) 4 x 102N;4.6 Km/s
4) 4 x 10°N,5.3 Km/s​

Answer 1

Answer:

The answer is 1000 x 2.303 × 2  m/s

Explanation:

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  

As we know, upthrust =u(dm/dt)= 1000 x 20 =  20000 N

=1.536×105N  

As v =uloge(m0/m)  

when the mass 1/100

then, v= 1000 loge (m0/m0/100)

v = 1000 x 2.303log10(100)

  = 1000 x 2.303 × 2  m/s

Answer 2

Answer:

As it consumes 20 kg

1000 x 2. 303 x 2m/s