ENERGY

the ability to do work

(cause motion or change)

Example: light, sound

Kinetic energy

energy a moving object

has because of its motion 

Example:

falling apple

potential energy

stored energy due to position

Example: sled at top of hill 

Elastic potential energy

energy stored by something that

can stretch or compress

Example:  stretched rubber band

Chemical

Potential Energy

energy stored in chemical bonds

Example: food, gasoline

Gravitational

Potential Energy

energy stored by objects due to

their position above the Earth's surface

Example:  apple in a tree

Law of Conservation of Energy

energy cannot be created or destroyed

changes from one form to another

Example: PE of stretched rubber band changes to KE of flying band

Work

transfer of energy that

occurs when

a force

makes an object move

Ex. lift a book

Work equation

= force (Newtons) x distance (meters)

Example:

1N x 1meter = 1Nm = 1Joule

Power

amount of work

done in one second;

rate at which work is done

Example: Watt (1 joule/1second)

machine

device that makes

doing work easier by

increasing the force applied 

or

changing the direction of the force 

Example: gear

inclined plane

block & tackle

example of a simple machine that

allows you to use less force

over a greater distance

fixed pulley

wedge

gears

example of a simple machine that

can change the direction of the effort force

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input force

force applied to the machine

(aka effort)

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output force

force applied by the machine

mechanical

advantage

= Fout/Fin

how much a machine

multiplies your input/effort

machine that does work with

only one movement

lever

bar that is free to

pivot around a fixed point

1st class lever

lever in which the

fulcrum is in between

effort (input) and resistance (output)

3rd class lever

lever in which the effort (input)

is in between

the fulcrum and the resistance (output)

2nd Class Lever

lever in which

the resistance (output) is in between

the fulcrum and the effort (input)

pulley

grooved wheel with a

rope, chain, or cable

running along the groove

block and tackle

system of fixed

and movable pulleys

simple machine

consisting of a shaft or axle

attached to the center of a

larger wheel,

so that they rotate together

sloping surface such as a ramp

that reduces the amount of

force required to do work

wedge

inclined plane with 2 sloping sides;

increases the input force and

changes the direction of the input force

screw

inclined plane wrapped around a cylinderical post;

the closer the threads, the more mechanical advantage but the more turns needed

two or more simple machines

that operate together

lever, wheel & axle, pulley,

inclined plane, screw, wedge

6 simple machines