Machines give us a mechanical _______ because they reduce the amount of effort needed to carry out a task.
advantage
Machines reduce the amount of ____ needed to carry out a task.
effort
an ______ _____ is a type of simple machine. It needs less effort to push a heavy object up a slope.
inclined plane
a ____ has a fixed support point or culcrum and a rigid bar.
lever
a force _______ on one end of the bar is transferred to the other end.
downward
The most basic circular tool is a _______.
roller
The ____ is the most important and earliest human invention.
wheel
A wheel has a circular part with a long rod or ____ going through the middle of it.
axle
The contact between the object and the ground creates a force called _____.
friction
Friction forces work in the _____ direction of the movement.
opposite
A ______ is a machine that uses wheels to lift an object.
pulley
