AAMC FL3 Chm/Phys q8

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vgp1993
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AAMC FL3 Chm/Phys q8

Post by vgp1993 » Fri May 18, 2018 12:03 pm

I'm having trouble following the aamc's explanation, so I was wondering if someone could help with this one.

Thanks!
NS_Tutor_Bryan
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Re: AAMC FL3 Chm/Phys q8

Post by NS_Tutor_Bryan » Wed May 23, 2018 11:42 am

Hey,

The AAMC explanation gives us all of the information we need, but it doesn't really explain it in the clearest way.

First, the question asks for the graph of v vs. t when using the generator-braking system. Our first step is to go back to the passage to see what it had to say about the generator-braking system.

In the second paragraph of the passage we read, "Engaging the generator to the wheels puts a decelerating force...and the force declines linearly with speed."

So if you were graphing F vs. v you'd get a decreasing linear curve.

We want to remember Newton's second law: F = ma and remember that F and a are directly related to each other.

So if a graph of F vs. v would get a linearly decreasing curve, then a graph of a vs. v would do the same thing.

Now we know that acceleration, a, is decreasing.

The final step here is remembering that acceleration is v/t. And that a graph of v vs t (like in the answer choices) shows us acceleration by looking at the slope of the v vs. t curve. Here's a picture to help clarify:
Screen Shot 2018-05-23 at 8.32.31 AM.png
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