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Energy and Its Forms - PowerPoint PPT Presentation

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Ch 15.1. Energy and Its Forms. Energy and Work. Work is done when a force moves an object a distance Work is a transfer of energy. Energy is the ability to do work Both measured in J. Kinetic Energy. Energy of motion Depends on mass and speed. KE = ½ mv2 SI Units: KE- m- v-.

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Ch 15 1

Ch 15.1

Energy and Its Forms

Energy and work
Energy and Work

  • Work is done when a force moves an object a distance

  • Work is a transfer of energy

  • Energy is the ability to do work

  • Both measured in J

Kinetic energy
Kinetic Energy

  • Energy of motion

  • Depends on mass and speed

  • KE = ½ mv2

    SI Units:

  • KE-

  • m-

  • v-

Ke practice
KE Practice

  • A 0.10 kg bird is flying at a constant speed of 8 m/s. What is the birds kinetic energy?

  • Given:

  • Formula:

  • Solve:

Potential energy
Potential Energy

  • Energy that is stored due to position or shape

  • Stored energy turns into KE

Potential energy1
Potential Energy

  • PE that depends upon an objects height

  • Increases with increased height

  • PE = mgh

    SI Unit

  • m-

  • g-

  • h-

  • PE that is stretched or compressed

  • Object springs back to its original shape

Gravitational PE

Elastic PE

Forms of energy
Forms of Energy

  • Energy associated with motion and position of everyday objects

  • Sum of PE and KE

  • Total PE and KE of all the microscopic particles in an object

  • Particles move faster, becoming warmer



Forms of energy1
Forms of Energy

  • Energy stored in chemical bonds

  • Energy associated with electric charges



Forms of energy2
Forms of Energy

  • Form of energy that travels through space in the form of waves

  • Energy stored in the atomic nucleus

    • Fission- releases energy, splits apart

    • Fusion- releases energy, comes together




Energy Conversion and Conservation

Conservation of energy
Conservation of Energy

  • Energy cannot be created or destroyed

    • It is transferred or converted

Energy conversion
Energy Conversion

  • Energy can be converted from 1 form to another

  • Process of changing energy – energy conversion

  • Gravitational PE converts into KE as an object falls

Energy conversions
Energy Conversions

  • Pendulums

    • PE constantly converted back and forth to KE

    • Stays in motion due to weight

  • Pole Vaults

Energy conversion calculations
Energy Conversion Calculations

  • KE + PE = KE + PE

    (Beginning) (End)

  • KE=

  • PE=

Conversion practice
Conversion Practice

  • A 1.50kg brick is dropped from rest and hits the ground at a speed of 26m/s. Ignore air resistance, calculate PE before the brick was dropped.

  • Given:

  • Formula:

  • Solve:

Energy and mass
Energy and Mass

  • Albert Einstein

    • Theory of Relativity

    • E = mc2

    • Energy and mass are equivalent and can be converted into each other

    • c= speed of light 3.0 x 108 m/s

Ch 15 3

Ch 15.3

Energy Resources

Nonrenewable energy
Nonrenewable Energy

  • Exists in limited quantities

  • Once used, it can’t be replaced except over the course of millions of years

    • Natural Gas

    • Coal

    • Uranium

  • Also known as fossil fuels

Renewable energy
Renewable Energy

  • Can be replaced in relativity short periods of time

Renewable energy1
Renewable Energy

  • Hydroelectric

    • Energy from flowing water

  • Solar

    • Sunlight converted into useable energy

Renewable energy2
Renewable Energy

  • Geothermal

    • Thermal energy beneath Earths surface

  • Others

    • Biomass Energy

      • Energy stored in living things

    • Hydrogen Fuel

      • Creates electricity by reacting hydrogen and oxygen

Conserving energy resources
Conserving Energy Resources

  • Reduce energy needs

  • Increase the efficiency of energy use