Question

Jerome plays middle linebacker for souths varsity football team. In a game against cross-town rival north, he delivered a hit to north’s 82-kg running back, changing his eastward velocity of 5.6 m/s into a westward velocity of 2.5 m/s. Determine that momentum change of the running back

Answer 1

Answer:

The change in momentum is 664.2 kgm/s in the westward direction.

Explanation:

Considering eastward direction as positive and westward direction as negative.

Given:

Mass of the running back is, $m=82\ kg$

Initial velocity of the running back is, $u=5.6\ m/s$

Final velocity of the running back is, $v=-2.5\ m/s$

Now, we know that, momentum is given as the product of mass and velocity.

So, initial momentum of the running back is given as:

$p_i=mu=82\times 5.6=459.2\ kgms^{-1}$

Final momentum of the running back is given as:

$p_f=mv=82\times -2.5=-205\ kgms^{-1}$

Now, change in momentum is given as the difference of final momentum and initial momentum.

Change in momentum = Final momentum - Initial momentum

⇒ $\Delta p=p_f-p_i$

⇒ $\Delta p=-205 - 459.2 = -664.2\ kgms^{-1}$

Therefore, the change in momentum is 664.2 kgm/s in the westward direction as the value is negative.