WEBVTT
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This is College Physics Answers
with Shaun Dychko.
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We need to find the pressure in
this hydraulic break system.
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So we can find the pressure anywhere...
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you know, in the slave cylinders or
in the master cylinder
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because the pressure is
the same throughout—
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that's what Pascal's principle says—
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and so we'll consider the pressure
created by the master cylinder
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because we have information about it.
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We know that 500 newtons ends up being
applied to this master cylinder
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and the diameter is 0.500 centimeters
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which we convert to meters by
noticing that the prefix
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'centa' means times 10 to the minus 2.
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So pressure is force divided by that area
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and it's a circular cross-section here—
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this cylinder is circular—
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and so the area is *π* times
its radius squared
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and its radius is half its diameter
so I have written
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*d* over 2 here and squared
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and then this works out to 4 times the force
divided by *π* times the diameter squared.
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That's 4 times 500 newtons
divided by *π* times
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0.500 times 10 to the minus
2 meters squared
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which is 2.5 times 10 to the 7 pascals.