A car travels 75 mi/hr. How many hours will it take to travel 837 km? (Pick the answer closest to the correct answer, 1.61 km=1 mile)

6.9 hours

Explanation:

In order to solve this problem we'll convert 837 km to miles (another option would be to convert 75 mi/hr to km/hr). To make said conversion we'll use the given conversion factor:

Finally we calculate the time required to travel said distance at a constant speed of 75 mi/hr:

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied

the answer is symmetrical : )