# Physics

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A ball falls from the top of a building . through the air(air resistance is present) to the ground below. How does the KE just before hitting the ground compare to the PE at the top of the building?

Isn't KE and PE equal to each other in this situation? Since I believe energey is conserved.

A ball droped some distance gains 30 J of Ke. Don't ignore air resistance. How much GPE did the ball lose?

Wouldn't the ball lose 30 J of gravitational potential energy?

• Physics -

If you account for friction, the KE has to be less than the original PE.

On the second, the GPE had to be greater than the finalKE. You have to know more about the air resistance to put a number of GPE.

If you ignore air resistance, then you are correct.

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