Notes

Energy

The ability to do work

Measured in Joules

Energy is used to do work and objects gain energy if work is being done on that object

5 forms of energy are
Heat
Chemical
Electromagnetic
Nuclear
Mechanical

Internal motion of atoms - heat energy
can be caused by friction
causes change in temperature and phase of matter

Chemical nrg - required to bond atoms
when bond broken energy is released

fuel and food are forms of stored chem nrg

power lines carry electromagnetic nrg to your house in the form of electricity
light - xample of electromag nrg
each colour shows diffrent amnts of nrg
Electro mag nrg can be carried by x wave, radio waves, laser light

Nucleus - source of nuclear nrg
Nucleus nrg is released when nuclei bond or split
NUCLEUR NRG IS MOST concentrated form of nrg

When work is done to an object, it gains Mechanical energy
ex-when kick a football, you do work to the football and give it nrg

Energy Conversion
Energy can be converted to any other type of energy
The sun’s energy through solar cells can be converted directly into electricity.
Green plants convert the sun’s energy (electromagnetic) into starches and sugars (chemical energy).
In an electric motor, electromagnetic energy is converted to mechanical energy.
In a battery, chemical energy is converted into electromagnetic energy.
The mechanical energy of a waterfall is converted to electrical energy in a generator.
In an automobile engine, fuel is burned to convert chemical energy into heat energy. The heat energy is then changed into mechanical energy.

Energy come in 2 forms
Kinetic Energy - energy of motion.
Potential Energy - stored energy.

Kinetic
The energy of motion is called kinetic energy.
The faster a object is, the more kinetic energy it has.
The greater the mass of a moving object, the more kinetic energy it has.
Kinetic energy depends on mass and velocity

K.E. = mass x velocity(to the second)/2

Potenial
Stored energy
EX - a bow pulled back

Potential energy that is dependent on height is called gravitational potential energy. (GPE)
Energy that is stored due to being stretched or compressed is called elastic potential energy. - Waterfall, falling snowflake, etc.
If you stand on a 3-meter diving board, you have 3 times the G.P.E, than you had on a 1-meter diving board.
Objects with more mass have greater G.P.E. - G.P.E. = Weight X Height.
Roller costers use Kinetic nrg
Basketball Kinetic nrg- http://images.slideplayer.com/27/9072572/slides/slide_15.jpg

Law of Conservation of energ
Energy can be neither created nor destroyed by ordinary means.
It can only be converted from one form to another.
If energy seems to disappear, then scientists look for it – leading to many important discoveries.
In 1905, Albert Einstein said that mass and energy can be converted into each other.
He showed that if matter is destroyed, energy is created, and if energy is destroyed mass is created.
E = MC squared