Simple Machines

Work

The amount of energy transferred by a force applied through a finite distance in the direction of the motion

Joule

units of work - 1Nm

Power

the rate of doing work; the rate at which energy is transferred

Watt

Units of power- 1 J/s

kilowatt

1000 watts of 10³ watts

machine

a device for multiplying forces or simply changing the direction of the force; does not make work less

rotational work

work done when spinning or rotating

simple machine

a basic machine where we assume effort y is 100%, generally refers to the 3-6 machines identified as classical simple machines.

efficiency

ratio of useful work output to total work input; can never exceed 100%

mechanical advantage

ratio of output to input force.

lever

an arm that pivots or turns against the fulcrum

fulcrum

pivot point of a lever

effort

force applied to a lever

resistance

first class lever

The fulcrum is located between the effort and the resistance

second class lever

the resistance is between the effort and the fulcrum

third class lever

the effort is between the load and the fulcrum

inclined plane

a stationary sloping surface used to raise heavy loads with less effort than lifting straight up

wheel and axle

pulley

a grooved wheel that turns around an axle; changes the direction of the force