Energy

• Energy – The ability to do work.

• The sun is going to die!!

• Oh No!!

• (in 5,000,000,000 years)

Mechanical EnergyMechanical Energy

Total energy of motion and position Total energy of motion and position of an object.of an object.

It can be all potential energy, all It can be all potential energy, all kinetic energy, or some of both.kinetic energy, or some of both.

Kinetic EnergyKinetic Energy

The energy of motionThe energy of motion

Potential Energy – Potential Energy – The stored The stored energy that result from the position or energy that result from the position or

shape of an object.shape of an object. Elastic potential energy –The potential energy Elastic potential energy –The potential energy

associated with objects that can be compressed associated with objects that can be compressed or stretched. or stretched.

Gravitational potential energy – Potential energy Gravitational potential energy – Potential energy related to an objects height. Weight x Heightrelated to an objects height. Weight x Height

There are 6 Forms of Energy• 1) Mechanical

• a) Kinetic energy- energy of a moving object. ex.- rock rolling down a hill.

• kinetic energy = 1/2 mv2

• example; a 20 kg goat ran at 3 m/s.

• 20kg x (3m/s) 2 = 20kg x 9 m/s2 = 180 = 90 J

• 2 2 2

– b) Potential Energy- “possible” energy that an object has because of its position-. ex- rock on top of a hill.

• Potential energy= mass x gravity x height ( g=9.8 m/s/s)

• Example: a 40 kg skateboarder is on a 2m ramp.

• 40 kg x 9.8 m/s/s x 2m = 784 J

2) Chemical energy- 2) Chemical energy- Potential energy Potential energy stored in the chemical bonds that stored in the chemical bonds that hold molecules together. hold molecules together. Chemical Chemical energy is stored in food, fossil fuels energy is stored in food, fossil fuels (gasoline, oil, coal), batteries, and (gasoline, oil, coal), batteries, and wood and cells in our bodies.wood and cells in our bodies.

3) Electrical energy- 3) Electrical energy- Energy of moving Energy of moving electrons. It is often an “in- between” form electrons. It is often an “in- between” form between 2 other forms of energy.between 2 other forms of energy. Can be kinetic Can be kinetic or potential or potential

Examples- electric heater, blender.Examples- electric heater, blender.power plant (burns coal) →→power lines→→→blenderpower plant (burns coal) →→power lines→→→blender

(chemical- thermal)(chemical- thermal) (electrical) (electrical) (kinetic)(kinetic)

4) Electromagnetic ( or radiant) 4) Electromagnetic ( or radiant) energy:energy: The energy of waves. The energy of waves.

Red orange, yellow, green blue indigo violet

Visible light is only 1/1000th of the electromagnetic spectrum.

Thermal EnergyThermal EnergyThermal energy is the total potential

and kinetic energy of particles in an object.

(You should know about this already!)(You should know about this already!)

6) Nuclear energy- 6) Nuclear energy- Energy locked in Energy locked in atoms. The energy can be released by atoms. The energy can be released by splitting atoms splitting atoms (known as fission- This (known as fission- This happens in nuclear power plants)happens in nuclear power plants) or by or by combining atoms combining atoms (known as fusion- (known as fusion- happens in the sun and in nuclear happens in the sun and in nuclear bombs) bombs)

FusionFusion Fission Fission

Renewable vs. Nonrenewable Renewable vs. Nonrenewable energyenergy

Energy sources can be either-Energy sources can be either- 1) Renewable- 1) Renewable- The source is The source is

replenished (comes back) quickly by replenished (comes back) quickly by natural processes.natural processes. Examples- wind, Examples- wind, solar, hydropower (dams), geothermal solar, hydropower (dams), geothermal (heat from underground), plants, (heat from underground), plants, trees (some), cow dung.trees (some), cow dung.

Non Renewable Non Renewable

Energy Resources that cannot be Energy Resources that cannot be replaced after they are used or can replaced after they are used or can be replaced only over thousands or be replaced only over thousands or millions of years.millions of years.

Fossil fuels are the most important Fossil fuels are the most important non-renewable resourcesnon-renewable resources..

2) Nonrenewable- 2) Nonrenewable- The source is used The source is used up and it is not replaced. up and it is not replaced.

Examples -fossil fuels (coal, oil, Examples -fossil fuels (coal, oil, gasoline), uranium gasoline), uranium (nuclear power (nuclear power source), trees (some)source), trees (some)