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Reply 20
Avatar for Zacken
Zacken
22
Original post by Steelmeat
How do i do part C?


Find the tension in terms of k and then set T > 0 and solve for k.
Reply 21
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Steelmeat
OP
2
Original post by Zacken
Find the tension in terms of k and then set T > 0 and solve for k.


I don't understand how i would do that?

currently for part b i have the expressionT=W3−kW2T=\dfrac{W}{3} - \dfrac{kW}{2}

not sure where to go from there
(edited 7 years ago)
Reply 22
Avatar for Zacken
Zacken
22
Original post by Steelmeat
I don't understand how i would do that?

currently for part b i have the expressionT=w3−kW2T=\dfrac{w}{3} - \dfrac{kW}{2}

not sure where to go from there


What on earth is ww?

Anyways... I get T=W6(2−3k)T = \frac{W}{6}(2-3k) in (b).
Reply 23
Avatar for Steelmeat
Steelmeat
OP
2
Original post by Zacken
What on earth is ww?

Anyways... I get T=W6(2−3k)T = \frac{W}{6}(2-3k) in (b).


sorry i made a mistake, i was supposed to make it captial

but yea uu got the same thing as me written in a different form....
Reply 24
Avatar for Zacken
Zacken
22
Original post by Steelmeat
sorry i made a mistake, i was supposed to make it captial

but yea uu got the same thing as me written in a different form....


Right, so make that >0 and solve for k.
Reply 25
Avatar for Steelmeat
Steelmeat
OP
2
Original post by Zacken
Right, so make that >0 and solve for k.


hmmm do i just say then

0<W3−kW20<\dfrac{W}{3} - \dfrac{kW}{2}
Reply 26
Avatar for Zacken
Zacken
22
Original post by Steelmeat
hmmm do i just say then

0<W3−kW20<\dfrac{W}{3} - \dfrac{kW}{2}


Now solve for kk:

W6(2−3k)>0  ⟺  2−3k>0  ⟺  ⋯\displaystyle \frac{W}{6}(2-3k) > 0 \iff 2-3k > 0 \iff \cdots
Reply 27
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Steelmeat
OP
2
Original post by Zacken
Now solve for kk:

W6(2−3k)>0  ⟺  2−3k>0  ⟺  ⋯\displaystyle \frac{W}{6}(2-3k) > 0 \iff 2-3k > 0 \iff \cdots


so k<23k<\dfrac{2}{3}?
Reply 28
Avatar for Zacken
Zacken
22
Original post by Steelmeat
so k<23k<\dfrac{2}{3}?


Yeah.
Reply 29
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Steelmeat
OP
2
Original post by Zacken
Yeah.


ah thanks again :smile:
Reply 30
Avatar for Zacken
Zacken
22
Original post by Steelmeat
ah thanks again :smile:


Sure.
how is part C done in this???!!! I'm stuck on it
Original post by Steelmeat
I don't understand how i would do that?

currently for part b i have the expressionT=W3−kW2T=\dfrac{W}{3} - \dfrac{kW}{2}

not sure where to go from there


Original post by Zacken
What on earth is ww?

Anyways... I get T=W6(2−3k)T = \frac{W}{6}(2-3k) in (b).


Original post by Steelmeat
hmmm do i just say then

0<W3−kW20<\dfrac{W}{3} - \dfrac{kW}{2}


^^ do everything above do part B and find an expression for T in terms of everything else
the set the big half of the expression >0 then solve for k
Original post by pondsteps
how is part C done in this???!!! I'm stuck on it
Reply 33
Avatar for Zacken
Zacken
22
Original post by pondsteps
how is part C done in this???!!! I'm stuck on it


Did you read the thread?
Original post by Steelmeat
I don't understand how i would do that?

currently for part b i have the expressionT=W3−kW2T=\dfrac{W}{3} - \dfrac{kW}{2}

not sure where to go from there

is it right if we kept the expression in this form?
Original post by poundsoffat
^^ do everything above do part B and find an expression for T in terms of everything else
the set the big half of the expression >0 then solve for k


why do we set it to > 0
Original post by pondsteps
is it right if we kept the expression in this form?

yes it's fine Zacken's format or Steelmeat's format are both fine

Original post by pondsteps
why do we set it to > 0


well if k=0 it doesn't have a value xD
if k<0 then k is negative which you don't want
Reply 37
Avatar for Zacken
Zacken
22
Original post by pondsteps
why do we set it to > 0


That's the definition of something being taut, it's tension is greater than 0. You should brush up your mechanical concepts.
Original post by Zacken
That's the definition of something being taut, it's tension is greater than 0. You should brush up your mechanical concepts.


ohh okay thanks. if its slack then the tension = 0 ?
Reply 39
Avatar for Zacken
Zacken
22
Original post by pondsteps
ohh okay thanks. if its slack then the tension = 0 ?


Yeah.

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