Question

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.​

Answer 1

Answer:

upthrust = mv/t

= 20×1000 = 20000 N

1/100 of initial mass = 20/100 kg/sec

therefore,

velocity = 20000×100/20 = 100000 m/sec

Answer 2

ANSWER:

The consumption of rocket fuel for the takeoff is 20 kg.

The release of escape gas velocity is equivalent to 1000 m/sec

Therefore, the upthrust received by the rocket is calculated as

The mass of fuel per time consumption by the rocket in travelling upward is $\frac{d m}{d t}=20$

Upthrust achieved by the rocket in travelling upwards = 20 x 1000 = 20000 N

The velocity acquired when the mass is considered 1/100 of the initial mass

$v=u \log e\left(\frac{m_{o}}{m}\ri)$

$v=1000 \times 2.303 \log 10(100)$

$v=4606 \mathrm{m} / \mathrm{sec}$