## 06-33 Kinetic Energy Solution

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Now, you could have solve this problem using the equation of motion that we learned about in unit 2
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or you could have use our new super cool technique of the work energy theory,
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which is how I'm going to solve this one.
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For work energy theory, first we need the total work and that is given by this equation.
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Well, let's look at the forces on the ball.
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Well, this is an easy one, there is only gravity pointing downwards.
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Okay, and Δx, well, we're just going to use this distance 57 meters.
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W = mg * 57 and that is also equal to the change in kinetic energy.
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And notice that an amazing but necessary thing happens, the mass cancels out.
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I can also multiply both sides by 2.
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Oh and don't forget that the initial velocity was zero since it was released from rest,
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and now, we have this equation.
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I just take the square root of both sides, and I get the final velocity of 34 m/s.
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So, now, we have another tool to solve this problem.
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We'll find there's actually places where this tool will solve problems that our previous tools couldn't.
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I think I teased you a little too much when I said,
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I don't know what energy is, but I know what energy does.
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Let's dove into that a little more deeply.
Title:
06-33 Kinetic Energy Solution
Description:

All units in this course below:

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Team:
Udacity
Project:
PH100 - Intro to Physics
Duration:
01:02