to the wheel turns the axle, or effort applied to the
axle turns the wheel. They move together. When effort
is applied to the wheel, the wheel and axle spreads the
force over a greater distance. If the radius of the wheel
is two times larger than the radius of the axle, every
time you turn the wheel once, the force will be multiplied
by two. A wheel and axle can produce a gain in either
effort or distance, depending on how it is used.
a wheel and axle can be found in doorknobs, roller skates,
and the handles of a faucet.