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04-02 Galileo's 2D Experiment

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    How did Galileo quantify motion in 2 dimensions? Well, he was a good scientist so he did an experiment.
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    This experiment involved rolling balls off of a the table and controlling
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    the speed with which they rolled off the table and measuring where the ball landed.
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    Galileo controlled the speed of the ball by adjusting the height from which it rolled.
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    If he wanted it to go faster, he will roll it from higher up.
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    We'll talk later about how exactly he can know where to put the ball.
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    Galileo controlled the speed of the ball by adjusting where in the plane he released it from.
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    Higher up of course meant it would be going faster by the time it got to the edge of the table.
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    Like in his previous experiments, he didn't know
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    the units of his velocity, but he knew their relative sizes.
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    For example, he knew he can make the velocity twice as big as it was originally
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    or three or four times bigger and look what he found.
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    Again these are unit list distances but look at this correspondence.
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    When the ball had a velocity of 1 unit, represented here, the trajectory looks something
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    like this. With a velocity of 2 units, the ball went twice as far.
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    Likewise with 3 and 4 units of initial horizontal velocity.
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    Galileo called this Vx. This x indicates an x direction.
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    When we label axis, we usually called the horizontal direction x and the vertical y
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    and so this x is just here to remind us that we're talking about a velocity in the horizontal direction.
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    Okay, this is pretty interesting. What's the conclusion that we can draw from this data?
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    Is it that the horizontal velocity is equal to the motion in the x direction?
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    That horizontal velocity is somehow proportional to the motion in the x direction?
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    Or that horizontal velocity and x direction motion are totally unrelated?
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    What's the best answer?
Title:
04-02 Galileo's 2D Experiment
Video Language:
English
Team:
Udacity
Project:
PH100 - Intro to Physics
Duration:
01:36
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