How does friction affect the output of machines?

Friction is cased by parts of the machine rubbing past one another. When this happens the parts tend to stick to each other which slows down the machine and heats up the parts. Thus the energy used to drive the machine is diverted from the purpose for which the machine was constructed and the machine becomes less efficient.

To reduce friction and make the machine more efficient, lubricants (eg oil) are used to make sure that parts that come into contact can slide past one another more easily.

Friction causes machines to slow down, and heat up. effecting efficiency negatively

first off excess causes a decrease in speed increase in wear on parts. Also friction causes heat which causes metals to expand.

For optimal mechanical efficiency, friction is the enemy.

Friction decreases efficiency. This is because when there is friction, heat is created. Therefore some energy is lost in the form of heat.

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure