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02ps-09 Distance To The Moon Solution

  • 0:00 - 0:06
    Well, let's see. The circumference is 10,900, and that must be π * d.
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    That means that the diameter is 10,900/π, which is about 3.14.
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    This gives me a diameter of the moon of about 3,470 km.
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    Now, to calculate this length--well, this is something you've done plenty of.
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    This is a simple tree problem.
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    We have a right triangle, we have the opposite side, and we want the adjacent side.
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    In fact, we know that the tangent of this angle--the tangent of this is 0.5 degrees--
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    has to equal the opposite side d, which is 3,470, over the side we want to calculate--L.
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    Now we can massage this equation a little bit,
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    bring L up and tangent down
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    and plug this into our calculator,
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    and we get an answer of 398,000 km.
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    This is really amazing what we've done.
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    I mean, you've learned a little bit of trig and geometry
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    and from that you've calculated the size of the earth, the size of the moon,
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    and the distance between the earth and the moon. That's really impressive.
Title:
02ps-09 Distance To The Moon Solution
Video Language:
English
Team:
Udacity
Project:
PH100 - Intro to Physics
Duration:
01:10
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