ShmoopTube

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here's your shmoop du' jour brought to you by elephants sure they [elephants by a small lake]

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have good memories can distinguish between human languages and can

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communicate with each other but ask one of them to calculate kinetic energy and [woman asking elephants to calculate kinetic energy]

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see how far that gets you yeah an elephant and tiger are racing through

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the Serengeti National Park hoping to find some water the elephant weighs 12 [Elephant and tiger running through Serengeti]

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times as much as the tiger but the tiger runs twice as fast by what factor is the

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elephant's kinetic energy larger than the tigers kinetic energy

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[muttering] all right what to do what to do well

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wait a second we've got a handy little equation to calculate kinetic energy [boy thinking about how to solve the problem]

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it's even called the kinetic energy equation here it is kinetic energy

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equals one-half mass times velocity squared all right now we're not really

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[boy studying on a computer screen] doing any math here we're just trying to figure out how changing some parts of

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this equation alter the results in fact let's start off by having a kinetic

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energy equation for the tiger and the elephant and setting them equal to each

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other and since the numbers don't really matter we're just going to make the mass [kinetic energy equation for elephant and tiger]

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one and the velocity one for each of these majestic beasts in fact let's get

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rid of that whole one-half part of the equation too we don't need it not having

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actual numbers or units is kind of freaking us out right now but it's fine [woman screaming and tearing her hair]

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its fine.. we can deal with it so at this point both of these equations equal one

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that's what one times one squared comes out to now Ellee the elephant has 12

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times the mass of the tiger so we'll change that in her equation so if we

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stopped right here we'd find that our long-term trend has 12 times the kinetic [elephants walking together]

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energy of the stripy guy but the elephant is slower than the big feline

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in fact she's running half as fast in this quest for water so let's change [elephants travelling together slowly]

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that 1 squared to 1/2 squared well 1/2 squared equals 1/4 so now if we do the

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math I multiply 12 times 1/4 we'll find that the elephant has 3 times the

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kinetic energy that's it answer C is correct if you came up with answer B, 6

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you might have forgotten to square the velocity multiplied it and if you chose [schoolboy frustrated and smashes his laptop]

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A, 24 you might have thought the elephant running twice as fast as a tiger but

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really it's the other way around and if you chose D 72 well we all make a mistake [a boy wearing his shoes as gloves and pants on top of his head]

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sometimes so now if you're ever on the plains of Africa and you see a tiger in

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an elephant in a hurry to a watering hole you'll know how to think about their

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differences in kinetic energy just make sure you're doing this from a safe [man with white hair and a lab coat studying the tiger and the elephant]

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distance you wouldn't want to get in the way of either one of these guys [man in a lab coat trampled by elephant]

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