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Energy

When work is done, how energy is stored and changed from one form to another, and how power measures the rate of doing work.

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What this chapter covers

  1. Work

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    • When Work is DoneForce moves body in its direction.
    • Factors and Calculation of WorkForce times distance in its direction.

  2. Mechanical Energy

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    • EnergyCapacity to do work; unit joule.
    • Potential EnergyStored by position or changed shape.
    • Kinetic EnergyMotion energy; depends on mass, speed.
    • Differences between PE and KEPosition or state versus motion.

  3. Energy Conversion and Conservation

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    • Law of Conservation of Mechanical EnergyConserved without friction or air resistance.
    • Forms and Transformation of EnergyMechanical, heat, light, sound, electrical, nuclear.

  4. Power

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    • Definition and CalculationRate of doing work (P = W/t).
    • Units of PowerWatt, kilowatt and horse power.
    • ComparisonsPower depends on time; work doesn't.

Try a sample question

In a solar cell, which form of energy is converted into electrical energy?

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