Peoples Physics Book Version-2

(Marvins-Underground-K-12) #1

2.3. Key Concepts http://www.ck12.org


2.3 Key Concepts



  • Any object in motion has kinetic energy. Kinetic energy increases as the square of the velocity, so faster
    objects have much more kinetic energy than slower ones.

  • The energy associated with gravity is called gravitational potential energy. Near the surface of the earth, an
    object’s gravitational potential energy increases linearly with its height.

  • Molecules store chemical potential energy in the bonds between electrons; when these bonds are broken the
    released energy can be transferred into kinetic and/or potential energy. 1KCal (1 food Calorie) is equal to
    4180 Joules of stored chemical potential energy.

  • Energy can be transformed from one kind into another and exchanged between systems; if there appears to be
    less total energy in a system at the end of a process then at the beginning, the “lost” energy has been transferred
    to another system, often by heat or sound waves.

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