Question

Fuel is consumed at the rate of $100kg/s$ in a rocket. The exhaust gases are ejected at a speed of $4.5\times {10}^{-4}m/s$. Then the thrust experienced by the rocket is :

• A. $4.5\times {10}^{6}N$
• B. $5.5\times {10}^{6}N$
• C. $3.5\times {10}^{6}N$
• D. $6.72\times 106N$

Answer 1

The correct option is A $4.5\times {10}^{6}N$

Here, $\Delta m=100kg,\Delta t=1sec$,
Relative speed of gases $v_r=4.5\times {10}^{4}m/s$
Hence, thrust $=v_r\frac{\Delta m}{\Delta t}$
$=4.5\times {10}^4\times \frac{100}{1}$
$=4.5\times {10}^{6}newton$