Physics: Principles and ProblemsChapter 12:
Thermal EnergyProblem of the Week <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/ch12_title.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | Latent
Heat
The heat of vaporization for water is 2.26 MJ/kg. That means,
for 1 kg of water to change from a liquid to a gas, it must
absorb 2.26 million joules of energy. The reverse is also true:
when 1 kg of water vapor condenses to a liquid, it will release
2.26 million joules of energy. Essentially, water vapor stores
a lot of energy, potential energy, called latent heat. | Basically,
the sun puts energy into ocean water to make vapor in the atmosphere.
Then the vapor puts energy into a tornado as the gas returns
to a liquid.  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/lilGuy.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]>
| Tornado
Fuel
 <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0078458137/193800/ch12_tornado.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (7.0K)</a>]]>
With wind speeds of 200 mph, a tornado releases tremendous amounts
of kinetic energy at the rate of one billion watts. A tornado's
power output, however, pales in comparison to its mother thunderstorm
that can expend 40 trillion watts of power! The question is,
where do storms and tornadoes get all this energy? The answer
is latent heat. The average tornado forms as warm moist air
begins to rise. Because air pressure falls with height, the
rising air expands and cools. At sufficient height, the air
is cold enough that the water vapor starts to condense. The
trouble now begins; the condensing vapor releases latent heat.
Energy flows out into the air, heating it. The warmed air is
less dense and starts to rise even faster attaining speeds of
150 mph. As the thunderstorm continues to be fueled by the latent
heat of vapor, tornadoes may form. |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/POWproblem1.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | How
many gallons of water must condense to fuel a tornado-spawning
thunderstorm for half an hour? | | |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/POWproblem2.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | How
large (diameter) would a 25-ft deep lake be to hold all the
water calculated in Problem 1? |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/webLinks.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (1.0K)</a>]]> | One
of the many sites on tornadoes is http://www.sciam.com/explorations
/0895davies.html. A new window will open. |  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> | <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0078458137/193800/gutter.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> |
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