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November 01, 2025, 09:26:08 am
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Author Topic: Another problem  (Read 514 times)  Share 

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TyErd

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Another problem
« on: June 01, 2010, 04:52:23 pm »
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Question from the STAV 2010

Christine is bouncing on her trampoline. At her maximum bounce height the bottom of her feet are 1.5m above the level of the unstretched trampline surface. At the lowest point of her bounce the bottom of her feet are 0.4m below the unstretched llevel of the trampoline surface. Christine weights 48kg. What is the spring constant of the trampoline

When i did this i was 100% confident i got the correct answer but turns out i was wrong. What i did was use F=kx, where F=480N and x=0.4m which mean spring constant is 1200n/m. What did i do wrong?
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m@tty

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Re: Another problem
« Reply #1 on: June 01, 2010, 04:59:56 pm »
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The force is not constant, I think.

You need to use energy to determine the spring constant.



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EDIT: change height ... :buck2: ...
« Last Edit: June 01, 2010, 05:22:13 pm by m@tty »
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TyErd

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Re: Another problem
« Reply #2 on: June 01, 2010, 05:17:33 pm »
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the answer is actually 11400N/m
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m@tty

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Re: Another problem
« Reply #3 on: June 01, 2010, 05:21:08 pm »
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Ok, like an idiot I used only a portion of the height. Replace 0.4 for 1.9 and you get 11400N/m.
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