Question

What is the effect of friction on the efficiency of a machine?

Answer 1

Work is done when a force causes an object to move in the same direction that the force is applied. ... Friction reduces efficiency because when two surfaces slide past each other, friction resists their motion, and in real machines, some input work is always used to overcome friction.

hope it clarifies ur doubt dear friend..

Answer 2

They introduce losses and decrease efficiency.

Explanation:

The friction generates heat, which is an energy that should be converted in movement. That energy, by the form of heat, is a loss.

Decreasing the friction, by lubrication, you will decrease the losses and increase efficiency.