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Q & A: friction and speed

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Most recent answer: 10/22/2007
Q:
How does Friction affect speed?
- Hannah (age 12)
Lexington, Ohio, America
A:
That depends on how something is moving to begin with, and how the things near it are moving. Friction tends to make an object move along with its neighbors.  For example, if a big wind is blowing, friction between it and a leaf on the ground will get the leaf moving, speeding it up. But if a leaf is falling on a still day, friction with the air will slow it down.

Iíve seen some presentations where people say ífriction opposes motioní. But as the leaf example shows, thatís not always true. Friction opposes relative motion of an object and its neighbors. Whether you say that speeds the object up or slows it down depends on what you are choosing to call 'at rest'.

Mike W.

LeeH

(published on 10/22/2007)

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