Question

A 4.0 kg model rocket is launched, shooting 50.0 g of burned fuel from its exhaust at an average velocity of 625 m/s. What is the velocity of the rocket after the fuel has burned?

Answer 1

Answer:

Velocity of rocket will be equal to 7.81 m/sec

Explanation:

We have given mass of the rocket $m_1=4kg$

Mass of fuel is given $m_2=50gram=0.05kg$ ( As 1 kg is equal to 1000 gram )

Velocity of fuel $v_2$ = 625 m/sec

We have to find the velocity of rocket $v_1$

From conservation of momentum we know that initial momentum is equal to final momentum '

So $m_1v_1=m_2v_2$, here $m_1$ is mass of rocket $v_1$ is velocity of rocket $m_2$ is mass of fuel and $v_2$ is velocity of fuel

So $4\times v_1=625\times 0.05$

$v_1=7.81m/sec$

So velocity of rocket will be equal to 7.81 m/sec