Bungee question (1 Viewer)

harry4

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how did u do the question with the bungee jumper. i got the first marks but not the part where x>L
 

untouchablecuz

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find dx/dt<br>find value of t for this (like 4.something i THINK)<br>find x at this time<br>if x is greater than (125-L-2) then he hits the water
 

Dr. Zoidberg

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Yeaah, i did what study freak did, but i have a feeling that i still did it wrong. fail!

OMG!! didn't minus it by 125 and 2

Thought x was the displacement for the whole thing :S
 

lolokay

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yeah differentiate it, to get the stationary points

pretty sure i made a numerical error (or multiple - to many numbers!) in there somewhere but I got about 119 as the minimum points
 

study-freak

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yeah differentiate it, to get the stationary points

pretty sure i made a numerical error (or multiple - to many numbers!) in there somewhere but I got about 119 as the minimum points
minimum?
I thought it was maximum (couldn't be bothered to check it)

But anyway, the number I got seems similar to, if not the same as, yours.
 

Dr. Zoidberg

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What answer did you get? whether or not the guy's head stays out or goes into water
I got stays out

I got 12x m (where is some number lol)

But i forgot to minus it by 125 and 2 :S cuz i thought displacement for the second part was for the whole thing

Zoidberg never fails :)

Ugh, dumb Q but why differentiate? I was about to take the limiting value of t but saw it was 4 marks so i thought it must be something harder.
HAHa, That's true for human anatomy :p ;P

And yeah, differentiate to find max displacement
 

study-freak

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I got stays out

I got 12x m (where is some number lol)

But i forgot to minus it by 125 and 2 :S cuz i thought displacement for the second part was for the whole thing



HAHa, That's true for human anatomy :p ;P

And yeah, differentiate to find max displacement
I got the same, except I'm not sure about the number.
 

lolokay

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minimum?
I thought it was maximum (couldn't be bothered to check it)

But anyway, the number I got seems similar to, if not the same as, yours.
sorry, I meant the minimum height, which corresponds to the maximum displacement
 

untouchablecuz

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wait, you had to test the nature of the points

i went on the physical interpretation that when the rope begins to retract, theres a moment where v is zero
 

lolokay

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wait, you had to test the nature of the points

i went on the physical interpretation that when the rope begins to retract, theres a moment where v is zero
I didn't bother with testing the points. I just said something like "the first stationary point corresponds to the maximum length of the rope", but I don't think I will get full marks for this question
 

harry4

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i don't understand why you have to differentiate in the first place
 

eldore44

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I didnt work it out properly. I just said 125 = some equation with t.
Then said that if t =3pi/4 125< some equation with t. therefore will go into water. pretty sure its almost completely wrong.
 

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