A 1200 kg car is traveling at 4.00 m/s and strikes a wall. The car bounces off the wall with a velocity of 4.00 m/s in the opposite direction. If the car is in contact with the wall for 0.100 seconds, then the magnitude of the impulse on the car is
A) 12,400 kg m/s.
B) 10,200 kg m/s.
C) 9,600 kg m/s.
D) 8,400 kg m/s.
E) 2,900 kg m/s.

Question

Quizplus · Accepted Answer

First, we need to find the change in velocity of the car. Since the car bounces off the wall in the opposite direction, its change in velocity is 4.00 m/s - (-4.00 m/s) = 8.00 m/s. 
Now, we can use the impulse-momentum theorem: 
impulse = change in momentum = mass x change in velocity 
impulse = (1200 kg)(8.00 m/s) = 9,600 kg m/s. 
Therefore, the magnitude of the impulse on the car is 9,600 kg m/s.

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