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3.2 THERMODYNAMICS P32 001 A Temperature
of an object is a measure of the total kinetic energy within the object. Answer
true or false and justify your answer. Also, give an example to support your
answer. B A
1.0 L and a 3.0 L pots of water are placed upon identical heating elements
and heated for the same time interval. The initial temperature of water in
both pots is 6.0 oC. The final temperature of the 3.0 L pot
reaches 18.0 oC. What will be the rise
in temperature of the 1.0 L pot of water and its final temperature? If
the initial temperature of the water in both pots was 92 oC,
what would be the final temperature of the water in the two pots? C If
a fast-moving marble hits a random scatter of slow moving marbles, does the
fast marble speed up or slow down? Which gains and which loses kinetic
energy? How
do these questions relate to the direction of heat transfer?
View solution below only after you have completed the answering the question. |
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Solution A False Temperature is a measure of the
average translational kinetic energy of the molecules of the object. For example, consider two pots of
boiing water at 100 oC. One pot contains 1.0 L of boiling water
and the other 3.0 L of boiling water. The temperature of the water in the two
pots is the same (100 oC) but the total molecular kinetic energy
in the 3.0 L is
much greater than the 1.0 L pot. B When energy is added to an object the
rise in temperature can be calculated from the equation If the initial temperature of the water in the pots was 92 oC, then the final temperature of the water will be 100 oC since the water in both pots will start to boil. The energy input results in a change in phase and not to an increase in temperature. C A fast-moving marble will always slow down as kinetic energy will be transferred from the fast marble to the slower moving ones. Likewise, with heat. Heat is the transfer of energy from a hot region to a colder region. Molecules with more kinetic energy transfer some of their excess energy to the less energetic ones. However, the total energy before and after any collisions is the same. |
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VISUAL PHYSICS ONLINE http://www.physics.usyd.edu.au/teach_res/hsp/sp/spHome.htm If you have any feedback, comments,
suggestions or corrections please email: Ian Cooper
School of Physics University
of Sydney ian.cooper@sydney.edu.au |
