Question

momentum change of an object is always calculated as final momentum - initial momentum. momentum change = m·δv = (80 kg)·(-10 m/s) = -800 kg·m/s. you must apply an impulse of -800 n·s to stop the player! how much time would it take a force of -1800 n to stop the football player? multiple - choice question

Explanation:

Step1: Recall impulse - force - time relationship

The formula for impulse $J$ is $J = F\times t$, where $J$ is impulse, $F$ is force and $t$ is time. We know that $J=- 800\ N\cdot s$ and $F = - 800\ N$.

Step2: Solve for time

We can re - arrange the formula $J = F\times t$ to $t=\frac{J}{F}$. Substitute $J=-800\ N\cdot s$ and $F = - 800\ N$ into the formula. Then $t=\frac{-800\ N\cdot s}{-800\ N}=1.0\ s$.

Answer:

$1.0\ s$