Question

an object with a mass of 1.5 kg changes its velocity from +15 m/s to +22 m/s during a time interval of 3.5 seconds. what impulse was delivered to the object?
3.0 n·s
11 n·s
25 n·s
56 n·s

Explanation:

Step1: Recall impulse - momentum theorem

Impulse $J$ is equal to the change in momentum $\Delta p$. The formula for momentum is $p = mv$, so $\Delta p=m\Delta v$.

Step2: Calculate the change in velocity

$\Delta v=v_f - v_i$, where $v_f = 22\ m/s$ and $v_i = 15\ m/s$. So $\Delta v=22 - 15=7\ m/s$.

Step3: Calculate the change in momentum (impulse)

Given $m = 1.5\ kg$ and $\Delta v = 7\ m/s$, using $J=\Delta p=m\Delta v$, we have $J=1.5\times7 = 10.5\ N\cdot s\approx11\ N\cdot s$.

Answer:

11 N·s