A 4350-kg truck traveling on a bridge at a velocity of (96.2 km/h,45.3 km/h)passes over a 724-kg car traveling at a velocity of (112 km/h,-35.5 km/h).The net momentum of the system consisting of the car and truck is A)(9.35 * 10⁴ kg m/s,4.77 * 10⁴ kg m/s). B)(1.39 * 10⁵ kg m/s,6.19 * 10⁴ kg m/s). C)(1.39 * 10⁵ kg m/s,4.77 * 10⁴ kg m/s). D)(3.76 * 10⁴ kg m/s,2.45 * 10⁴ kg m/s). E)(1.39 * 10⁵ k m/s,-4.77 * 10⁴ kg m/s).

Question

Quizplus · Accepted Answer

We can begin by finding the momentum of the truck and car separately using the equation:
momentum = mass x velocity

For the truck: 
momentum = 4350 kg x (96.2 km/h, 45.3 km/h) = (4.18 x 10^5 kg m/s, 1.97 x 10^5 kg m/s)

For the car: 
momentum = 724 kg x (112 km/h, -35.5 km/h) = (8.12 x 10^4 kg m/s, -2.57 x 10^4 kg m/s)

We can then find the net momentum of the system by adding the individual momenta together:
net momentum = (4.18 x 10^5 kg m/s, 1.97 x 10^5 kg m/s) + (8.12 x 10^4 kg m/s, -2.57 x 10^4 kg m/s) = (5.99 x 10^5 kg m/s, 1.71 x 10^5 kg m/s)

Therefore, the best choice is C, which matches the calculated net momentum.

A 4350-Kg Truck Traveling on a Bridge at a Velocity