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Thank you We sneak and here's your shmoop too sure

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brought to you by falling objects The story goes that

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isaac newton discovered universal gravity when an apple conked him

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on the head But the real question is was it

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red or was it green All right a particle slides

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down a ramp and she tours on only often adds

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it is twenty meters tall if it's moving it twenty

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five meters a second in ways fifteen kilograms is it

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shoots off the edge How fast is it falling at

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the instant before it hits the ground right near the

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potential answers All right well just be interesting So how

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do we combine the horizontal speed of an object with

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its vertical speed from gravity to find out how fast

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it's falling thinking about terminal velocity here Well actually we

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don't combine them at all It doesn't matter how fast

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an object moves for izon aly the acceleration of gravity

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is a constant downward force They'll consider this if a

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bullets fired from a gun on a perfectly horizontal plane

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and at the same time a bullet drops from a

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hand at the same height as the gun Both bullets

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Will hit the ground at the exact same instant Pretty

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cool huh Yeah So let's address this question by first

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looking at the potential energy of the particle Potential energy

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remember equals mass times gravity times height All right well

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when we plug our numbers into that equation we see

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that the potential energy of this particle at the moment

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it leaves the ramp is three thousand jewels So speaking

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gravitationally the total mechanical energy at the moment the particle

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leaves the ramp is three thousand jewels After all mechanical

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energy equals potential energy plus kinetic energy And at the

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very instant the particle leaves the ramp it hasn't started

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falling yet So the kinetic energy is zero So what

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will the kinetic energy be right before the particle hits

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the ground Well at that point there will be no

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more potential energy So if the total mechanical energy of

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this system is three thousand jewels and the potential energy

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is zero then the kinetic energy will have to be

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three thousand jewels We have to remember the formula for

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kinetic energy which is kinetic energy equals one half mass

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times velocity squared right here saying wake unplugging our numbers

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and solve for velocity Well three thousand jewels equals one

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half times fifteen kilograms Times velocity squared little algebra and

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we'll see that the velocity is twenty meters a second

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So the correct answer is option a When dealing with

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falling objects potential energy is pretty much always involved Remember

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how to calculate it and remember how it relates to

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connecticut and mechanical energies but leave falling objects to theoretical

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problems In the real world they tend to cause issues 00:02:38.733 --> [endTime] now

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