I need help. I need to define friction. I know what it is but cant figure out how to put them in words with out being to long written.

Then I have two more ?s

What are the three types of friction?

What is the speed of acceleration due to the force of gravity?
please help

The second definition is good:
http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=1861613545

types of friction: rolling, kinetic, sliding, air, static,

The acceleration due to gravity is on the average 9.81m/s^2 at sea level.

1 answer

Do wheels reduce friction?