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Name:  Courtney S.
Status: student
Age: 10
Location: N/A
Country: N/A
Date: 2000-2001

Why does a whiffle ball filled with sand roll faster down a sloped driveway than an empty whiffle ball?

Because, for any given speed, the sand-filled ball has a larger momentum. This means that forces exerted by small impediments to rolling (e.g., drag, the effects of breezes, imperfections in the driveway surface) produce momentum changes that are a smaller fraction of the sand-filled ball's total momentum.

Tim Mooney

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