Question

Due to internal combustion inside a rocket, gases are ejected at the rate of 2.4 $\frac{kg}{minute}$. The velocity of the gases with respect to the rocket is 400 $\frac{m}{s}$. Calculate force exerted on the rocket. (Give your answer in N)

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Answer 1

Step 1: Since gases are ejected at the rate of 2.4 $\frac{kg}{minute}$, i.e. = $\frac{2.4}{60}$ $\frac{kg}{s}$

Change in momentum per second = v $\times$ $\frac{2.4}{60}$ = 400 $\times$ $\frac{2.4}{60}$

Step 2: Now since force, F = Rate of change of momentum = 400 $\times$ $\frac{2.4}{60}$ = 16 N