Classifying Friction

Most recent answer: 10/22/2007

Q:
Is friction energy?
- tony (age 12)
northern middle school, NC
A:
Tony -

Actually, no. Friction is what's called a 'force.' Forces are things that push or pull, and they're very different from energy. Friction is a force that makes the objects move together or at least have more nearly the same velocity.

However, this does involve energy. When the two items start rubbing, the fact that they are moving means that they have a certain amount of ’kinetic energy.’ As friction slows them down, some of that energy is transfered to the atoms and molecules on their surface, which get bumped around. It's still kinetic energy, but now it's the kinetic energy of the molecules rather than the entire objects. (It's sometimes also called ',' since the two surfaces generally heat up.)

-Tamara

(published on 10/22/2007)