How to re-arrange S = ut + 1/2at² to make T subject? Watch

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jasbirsingh
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#1
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#1
I know it's easier by putting in the number's first...But I need this equation for writing a program..So Please cany1 tell me how to re-arrange it because I have been trying to do but couldn't do it..
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shawrie777
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Make LHS=0 and use the quadratic formula
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Ezraeil
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...
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TI-84
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(Original post by SyedT)
s= ut + 0.5at^2

s = t^2(u/t + 0.5a)

s/t^2 = u + (0.5a)/t

t^2 = st/ (u + 0.5a)

t = s/(u+0.5a)
what's happening in that step?
If your trying to say that you've gone from
(u/t + 0.5a)
to
(u+0.5a)/t

then that's wrong.
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iainthegreat
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^ wrong. I don't think you can do it.
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Ezraeil
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(Original post by TI-84)
what's happening in that step?
If your trying to say that you've gone from
(u/t + 0.5a)
to
(u+0.5a)/t

then that's wrong.
Sorry about that,I made an error,I've edited my post.
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Plutoniummatt
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#7
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2nd order polynomial in t, use quad formula
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lolhenry
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You can't do it.
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cambo211
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surely its just +-sqrt((2(s-ut))/a)) = T
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03gshep
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#10
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(Original post by shawrie777)
Make LHS=0 and use the quadratic formula
+1
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cambo211
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(Original post by cambo211)
surely its just +-sqrt((2(s-ut))/a)) = T
oh wait
just realised t in UT

stupid me

but anyway

0 = 1/2at^2 + ut - s

then T = (-u +/- sqrt(u^2 + 2as))/a
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cambo211
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(Original post by lolhenry)
(2s)/(u+at)=t



or



t = -ut \pm \sqrt((ut)^2-2s)
which is what i did first but then you havnt got it in terms of t because you have t in both sides
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AarenHealy
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I made the LHS =o and completed the square and came to:

t= (-u +or- the square root of (2sa+u^2))/a

which is: -u plus or minus the square root of (2sa + u squared). Everything over a.

Is that right?
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03gshep
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(Original post by AarenHealy)
I made the LHS =o and completed the square and came to:

t= (-u +or- the square root of (2sa+u^2))/a

which is: -u plus or minus the square root of (2sa + u squared). Everything over a.

Is that right?
Yes
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lolhenry
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(Original post by cambo211)
which is what i did first but then you havnt got it in terms of t because you have t in both sides
Meaning you can't rearrange
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03gshep
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(Original post by lolhenry)
Meaning you can't rearrange
You can, using the formula like above.
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xSkyFire
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(Original post by jasbirsingh)
I know it's easier by putting in the number's first...But I need this equation for writing a program..So Please cany1 tell me how to re-arrange it because I have been trying to do but couldn't do it..
Do you HAVE to use this formula? Can't you just try another formula and work out an unknown from that, plug that unknown into a formula with T in it, then get T from that? That's what I do if I want to double check answers o.o
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dawgnut
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#18
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#18
Depends on your question, in some:

ut is usually = 0
so rearrage from S=1/2at^2?
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qgujxj39
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#19
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#19
Use the quadratic formula. Don't bother rearranging it, use the formula for each individual question.
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Rooster523
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#20
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#20
s=ut + 1/2at^2

s/t=u+1/2at

2s/t=u+at

2s/t-u=at

2s-u= at^2

2s-u/a= t^2

√(2s-u)/a= t

voila.
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