WEBVTT
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This is Giancoli Answers
with Mr. Dychko.
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First we'll calculate the amount
of energy absorbed by the soup,
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and that's 250 milliliters
is 0.25 liters,
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and times by the density of water,
1 kilogram per liter,
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to get the mass,
that together that makes the mass.
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And then times by 4,186
joules per kilogram Celsius degree
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in that specific heat capacity
of water
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and then times
by the change in temperature,
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final temperature of 75 degrees Celsius
minus the initial temperature of 15.
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And you get 62,790 joules
of energy need to be gained by the soup.
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So, power is energy
divided by time,
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energy in this case is *Q*.
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And then we'll solve for *t*
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by multiplying both sides
by *t* over *p*.
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So, on the left side were left
with *t*,
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on the right side we're left
with a *Q* over *p*.
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So, energy gained is heat
divided by power.
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So, that's, 62,790 joules
divided by 375 watts
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but watts are joules per second.
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And in this gives
about 170 seconds.