Work, Power and Simple Machines-8

Machine

A device which helps make work easier by changing the size, direction, or both size and direction of a force

Simple Machine

a device that completes a task and makes work easier

Work input

The work done on a machine

Work Output

The work done by a machine

Mechanical Advantage

A number/factor which tells how many times a machine multiplies force

Mechanical Advantage Formula

MA = Output force/Input force

Efficiency

The measure of how close the machine's output is to its input

Efficiency formula

Efficiency = (Output force/Input force) x 100

Six types of simple machines

Lever, Inclined plane, Wedge, Screw, Wheel and Axle and Pulley

Lever

A machine consisting of a bar that pivots at a fixed point. Fixed point = Fulcrum

Inclined Plane

A machine which is a straight, slanted surface, ramp.

Wedge

A machine which consists of a double inclined plane that moves. MA = length of wedge/thickness of wedge

Screw

A machine which is an inclined plane wrapped around a central cylinder

Wheel and Axle

A machine consisting of 2 circular objects of different sizes. Ex. Steering wheel

Pulley

A machine consisting of a grooved wheel which holds a rope or cable

3 types of Pulleys

Fixed, Moveable and Block and Tackle

Compound Machine

consists of two or more simple machines

Work

The action that results when a force causes an object to move in the direction that the force was applied. W=Fd

Joules

SI unit for work and energy, a Newton-meter (J)

Power

The rate at which work is done (How fast or slow) P=W/t

Watt

SI unit for power, a joule per second

The more distance

The more work you do