- #1

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2. x = ut + 1/2 at^2

3. u^2 = + 2ax

Can I use three equeations above for the same concept 'constant accelaration' interchangeablly?

- B
- Thread starter Indranil
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- #1

- 177

- 11

2. x = ut + 1/2 at^2

3. u^2 = + 2ax

Can I use three equeations above for the same concept 'constant accelaration' interchangeablly?

- #2

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What do you think? What conditions would have to be true for you to be able to use these three equations interchangeably?Can I use three equeations above for the same concept 'constant accelaration' interchangeablly?

- #3

Doc Al

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I would rewrite this one as v^2 = u^2 + 2ax, since you're using u as the initial velocity.3. u^2 = + 2ax

Those equations are valid for constant acceleration, but do they say the same thing? Hint: Note that each equation relates a different pair of "unknowns".Can I use three equeations above for the same concept 'constant accelaration' interchangeablly?

- #4

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If a = 0, we get 'velocity' in every equations.What do you think? What conditions would have to be true for you to be able to use these three equations interchangeably?

- #5

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But what about if ##a \neq 0##?If a = 0, we get 'velocity' in every equations.

- #6

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I think, I don't get 'velocity' in every eqeations.But what about if ##a \neq 0##?

- #7

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I'm not sure what you mean by "get velocity". Only the first equation is an equation for the velocity ##v##.I think, I don't get 'velocity' in every eqeations.

Perhaps we should take a step back and ask: why would you want to use these three equations interchangeably?

- #8

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To get the velocity either initial or final velocity. It is my own presumption. I may be wrong with this concept.I'm not sure what you mean by "get velocity". Only the first equation is an equation for the velocity ##v##.

Perhaps we should take a step back and ask: why would you want to use these three equations interchangeably?

- #9

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The initial velocity is just ##u##; you don't solve for that, it's something that should be given in the statement of the problem.To get the velocity either initial or final velocity.

The final velocity ##v## has to be obtained from the first equation. You can't obtain it from the second equation since it doesn't appear at all. The third equation has ##v## in it (at least, it does with the correction @Doc Al gave) but it also has ##x## in it, which is another unknown; so it won't give you ##v## in terms of quantities that are known from the statement of the problem.

- #10

Doc Al

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The first equation relates v & t.

The second equation relates x & t.

The third equation relates v & x.

So each equation describes constant acceleration motion in a different way. Depending upon the particular problem you're dealing with--and the information given--one equation might be more useful than another. While all three deal with accelerated motion, they are not the same.

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