Simple Machines

Inclined Plane

A simple machine that is a straight, slanted surface, which facilitates the raising of loads; a ramp

Wedge

A simple machine that is made up of two inclined planes and that moves; often used for cutting

Wheel & Axle

A simple machine consisting of two circular objects of different sizes; the wheel is the larger of the two circular objects(THE WHEEL IS NOT ALWAYS THE INPUT FORCE!!)

Lever

A simple machine that consists of a bar that pivots at a fixed point called a fulcrum.

Pulley

A simple machine that consists of a wheel over which a rope,chain or passes

Screw

A simple machine that consists of an inclined plane wrapped around a cylinder

Movable Pulley

Moves up with the load as the load is lifted. The mechanical advantage depends on how many strings directly support the load.

3rd class Lever

The input force is between the fulcrum and the load; Mechanical Advantage of less than 1.

2nd class Lever

The load is between the input force and the fulcrum; The closer the load is to the fulcrum, the greater the mechanical advantage is.

Machine

A device that helps do work by either overcoming a force or changing the direction of the applied force

Compound machine

A machine made up of more than one simple machine

Mechanical Advantage

A number that tells how many times a machine multiplies force.

Mechanical Efficiency

A quantity, usually expressed as a percentage, that measures the ratio of work output to work input in a machine.

Block & Tackle Pulley

Does not move, spins; The mechanical advantage depends on how many strings directly support the load.

1st class Lever

Fulcrum is between input force and the load;When F is closer to load than to input force, mechanical advantage of greater than 1; When F is exactly in the middle, mechanical advantage of 1; When F is closer to Input force than to load, mechanical advantage of less than 1.

Fixed Pulley

Only spins; Size of the output force is the same as the size of the input force; Provides a mechanical advantage of 1

Power

The rate at which work is done or energy is transformed.

Joule

The unit used to express energy; equivalent to the amount of work done by a force of 1 Newton acting through a distance of1 meter in the direction of the force.

Watt

The unit used to express power; equivalent to a joule per second.

Work Output

The work done by a machine; the product of the output and the distance through which the force is exerted.

Work Input

The work done on a machine; the product of the input force and the distance through which the force is exerted.

Work

This is done when a force causes an object to move in the direction of the force.