What is the ratio of output force to input force in a machine called?

Which simple machine consists of a rigid bar that pivots on a point?

What is the point around which a lever rotates?

Which type of pulley system reduces the amount of force needed to lift a load?

What is the formula for calculating mechanical advantage?

Which law of motion explains why a machine cannot be 100% efficient?

Which simple machine is a slanted surface used to raise objects?

The combination of two or more simple machines is called what?