Exploration 19.1: Mechanical Equivalent of Heat

Please wait for the animation to completely load.

As the 100-kg red mass drops, the paddle turns in the liquid and the liquid heats up. Joule used a version of this device to determine the equivalence between heat and work. You will run the animation to do the same (position is given in meters, time is given in seconds, and temperature is given in degrees Celsius). The temperature of the liquid is given by the thermometer shown. Restart.

The dimension of the container that holds the blue liquid that you cannot see (into the screen) is 0.1 m. The density of the liquid is 13,600 kg/m3.

  1. What is the volume of the liquid?
  2. What is the mass of the liquid?
  3. During the animation, what is the change in temperature of the liquid?
  4. If it takes 33 calories to raise 1 kg of the liquid 1oC, how much heat goes into the liquid?
  5. What is the change in kinetic energy of the falling red mass?
  6. What is the work done by gravity on the mass (in joules)?
  7. The work in (f) goes into frictional heating of the liquid (as the paddles turn through the liquid). Therefore, how many calories are equal to 1 Joule?

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Exploration authored by Anne J. Cox.
Script authored by Anne J. Cox and Mario Belloni.

Physlets were developed at Davidson College and converted from Java to JavaScript using the SwingJS system developed at St. Olaf College.

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Open Source Physics - EJS Modeling
Physlet Physics
Physlet Quantum Physics
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