Understanding the Force Exerted by a Small Rock on a Windshield

What is the magnitude of the force exerted on the windshield by a small rock?

A. Less than that exerted on the rock by the windshield
B. Greater than that exerted on the rock by the windshield
C. Equal to that exerted on the rock by the windshield
D. Equal to that exerted on the rock by the windshield only if you were accelerating when the rock hit the windshield

Answer:

The force exerted on the windshield by a small rock is equal to the force that the windshield exerts on the rock, according to Isaac Newton's Third Law of Motion. This is true regardless of whether or not the car was accelerating when the rock hit. So the correct option is C.

Explanation:

According to Isaac Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. In this case, the action is the force exerted by the small rock on the windshield, and the reaction is the force exerted by the windshield in response to the small rock.

So, the correct answer is C, equal to that exerted on the rock by the windshield. This means that the magnitude of the force that the rock has exerted on the windshield is exactly the same as the force that the windshield has exerted on the rock, just in the opposite direction. This law holds true regardless of whether you were accelerating or not when the rock hit the windshield.