The car A has a weight of 4000 lb and is traveling to the right at 3 ft/s. Meanwhile a 2000-lb car B is traveling at 6 ft/s to the left. If the cars crash head-on, and at a time instant during the crash the impact force on A is 900 lb to the left, what is magnitude and direction of the impact force exerted on B at the instant

900 lb to the right

Explanation:

Newton's third law of motion states that for every action there is equal and opposite reaction.

Hence if the two cars (i.e. car A and car B) crash head on and there is an impact on car A of 900 lb to the left, car B would have to generate a force of equal magnitude and in an opposite direction. Since car A had a force of 900 lb to the left, the impact force exerted on car B would be 900 lb to the right.

The answer is 900 lb to the right

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