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Unit of work in mechanics and thermo dynamics

  1. Feb 26, 2006 #1
    unit of work and unit of heat

    When we study dynamics,the unit of work is in joules which is the energy transfered to a mass which in turn is the product of force and the distance along which the force is applied

    When we study thermodynamics, the unit of work is again in joules.

    How these two can be same?
  2. jcsd
  3. Feb 26, 2006 #2
    Better, you say why should they be differant. What happens when an object does a work on an object? How do we measure work there?
  4. Feb 27, 2006 #3
    Work is a kind of energy. I think that the reason to call it work is historically in the context of vapor machines. We use energy to move something that can replace men's labour such as moving a piston or something else.

    The first law of thermodynamics says that the balance of energy is the rest (or the sum, depending on sign chriteria) of heat and work. It must have the same units so, but conceptually are different things. Work is a force times a displacement, energy that we use to move something. Heat is energy that we use to change the temperature of a system (for example).
  5. Feb 28, 2006 #4
    Work is not a kind of energy. Rather it's a way of transfering energy.
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