Friction is a force that opposes the relative movement of an object. Therefore extra force must be added to the work that the machine is doing in order to compensate for the loss of energy caused by friction.
Example: The hinges on a door are made up of two seperate pieces, one of them is on the wall and the other is attached to the door. When the door is opened the two pieces rub together and eventually the door will squeak and rust will begin to form. This can be prevented by adding oil to lubricate the hinges so that the door takes less effort to open.
Friction is a force that opposes the relative movement of an object.
Therefore extra force must be added to the work that the machine is doing in order to compensate for the loss of energy caused by friction.
Example: The hinges on a door are made up of two seperate pieces, one of them is on the wall and the other is attached to the door. When the door is opened the two pieces rub together and eventually the door will squeak and rust will begin to form. This can be prevented by adding oil to lubricate the hinges so that the door takes less effort to open.
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