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Rewriting equation

  • Thread starter 1MileCrash
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  • #1
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Homework Statement



This is for a physics problem. I need to solve this for d, but I'm not sure how.

Homework Equations





The Attempt at a Solution



I've gotten up to:

[itex]\frac{2d}{g} = (t - \frac{d}{v})^{2}[/itex]

When I multiply the right term out, it becomes a mess, everything I do makes it ugly. What should I try doing?

My main source of confusion is that multiplying that out gives me:

[itex]t^{2} - \frac{2dt}{v} + \frac{d^{2}}{v^{2}}[/itex]

While my solution manual gives the last term as:

(1+v^2)d^2.

Those are not the same. What gives?
 
Last edited:

Answers and Replies

  • #2
SammyS
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If squaring the right hand side makes it too ugly for you, then try taking the square root of both sides. That makes the math a little more challenging,

You could multiply both sides by v2 then square the right hand side. Maybe not quite so ugly.
 
  • #3
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If squaring the right hand side makes it too ugly for you, then try taking the square root of both sides. That makes the math a little more challenging,

You could multiply both sides by v2 then square the right hand side. Maybe not quite so ugly.
My main problem is that the solution manual I have gives steps that I just don't follow.

They multiply out (t-d/v)^2 and get (1+v^2)d^2 for the last term. I literally haven't the slightest how it comes to that, I just get plain old d^2/v^2.. and they aren't the same.
 
  • #4
SammyS
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How about scanning that solution & posting the image?
 
  • #5
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Sure thing, gimme a few minutes.
 
  • #6
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http://img585.imageshack.us/img585/5854/physicsstone.png [Broken]

After "square both sides to obtain.." I don't know how they get that. At all.
 
Last edited by a moderator:
  • #7
SammyS
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It's just a typo.

It could be (1 ÷ v2) d2

The following lines appear to be correct.
 

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