Recent content by smcclenaghan

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    Why Use Kinetic Energy Instead of Momentum to Stop a Car?

    I appreciate the response, NascentOxygen (and to you NTW).
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    Why Use Kinetic Energy Instead of Momentum to Stop a Car?

    Right. So if the question were asking how much force in X seconds, we'd be looking at the formula for momentum. And if the question were asking how much force in X meters, we'd be looking at the formula for KE. Am I on the right track? (I understand the original question is not answerable as...
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    Why Use Kinetic Energy Instead of Momentum to Stop a Car?

    Ok, I think I follow. If it is in seconds, we're looking at momentum. If it is in meters, we're looking at KE. Is that about right?
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    Why Use Kinetic Energy Instead of Momentum to Stop a Car?

    Homework Statement A 2000kg car is moving at 50km/h. What is the force required to stop it? Homework Equations KE=1/2m(v^2) p=m*v The Attempt at a Solution 1/2(2000kg)*(50km/h)^2 = 1000kg*2500km^2/h^2 = 2,500,000 km^2/h^2 converting from hours to seconds and km to m (to get joules)...