Question

a satellite with a mass of 120 kg fires its rocket thrusters, which give an impulse of 7440 kg·m/s. what was the total change in the velocity of the satellite - that is, what was the total δv?

a. 88 m/s
b. 45 m/s
c. 17 m/s
d. 62 m/s

Explanation:

Step1: Recall impulse - momentum theorem

Impulse $J$ is equal to the change in momentum $\Delta p$. And $\Delta p = m\Delta v$, where $m$ is mass and $\Delta v$ is change in velocity. So $J=m\Delta v$.

Step2: Solve for $\Delta v$

We know $J = 7440\ kg\cdot m/s$ and $m = 120\ kg$. Rearranging the formula $\Delta v=\frac{J}{m}$. Substituting the values, we get $\Delta v=\frac{7440}{120}$.
$\Delta v = 62\ m/s$

Answer:

D. 62 m/s