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November 01, 2025, 09:27:12 am
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Author Topic: slight freakout!  (Read 976 times)  Share 

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adelaide.emily10

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slight freakout!
« on: June 12, 2011, 07:50:44 pm »
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i found this formula and i have never seen it before:

Ek=p^2/2m
what is it?

p.s good luck everybody, fingers crossed VCAA won't be too mean this year :)
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luffy

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Re: slight freakout!
« Reply #1 on: June 12, 2011, 07:54:09 pm »
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Quote from: adelaide.emily10 on June 12, 2011, 07:50:44 pm
i found this formula and i have never seen it before:

Ek=p^2/2m
what is it?

p.s good luck everybody, fingers crossed VCAA won't be too mean this year :)

I've never seen it before either :P

But think about it - the equation makes perfect sense.

Ek = , where p = momentum







It simply relates momentum to kinetic energy.
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cohen

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Re: slight freakout!
« Reply #2 on: June 12, 2011, 07:54:33 pm »
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It's basically just a manipulation of the momentum formula (p=mv)
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adelaide.emily10

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Re: slight freakout!
« Reply #3 on: June 12, 2011, 07:56:13 pm »
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*face palms self* did not realise that, thanks peeps :D
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jinny1

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Re: slight freakout!
« Reply #4 on: June 13, 2011, 09:21:27 am »
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Has anyone encountered a question wher you would use that equation?
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VivaTequila

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Re: slight freakout!
« Reply #5 on: June 13, 2011, 10:18:33 am »
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why dont you just derive this stuff in the exam, it's not hard to work from basics
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adelaide.emily10

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Re: slight freakout!
« Reply #6 on: June 13, 2011, 05:44:17 pm »
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another question

materials and structures: if there are two materials that are brittle on a stress v starin graph, which one is more brittle?
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Asx4Life

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Re: slight freakout!
« Reply #7 on: June 13, 2011, 05:49:50 pm »
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the one that requires less strain to break
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meganelise

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Re: slight freakout!
« Reply #8 on: June 13, 2011, 06:10:44 pm »
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hey guys,
quick question - I've had a look at some other threads on sig figures, and the general feeling is that it doesn't matter too much for physics, unless the question specifically asks for significant figures.
despite this I've been chucking my answers down with what I would have thought were the significant figures from the question -
for eg. a question with 50m, 700kg, and 11200N is technically one sig figure? or should we be giving answers to the most (ie. 3 sig figures, which is what the answer suggests)

But of course the answers from all the practice exams (including vcaa) seem to be very inconsistent... even with answers using the same data... I can't work it out.

so any tips? should we go the most significant figures given (as in don't lose any)? or just whatever seems good? or will everything be okay as long as you've got your full answer in your working out and don't write anything ridiculous..

any thoughts on the matter would be reassuring for tomorrow.. thanks :)
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adelaide.emily10

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Re: slight freakout!
« Reply #9 on: June 13, 2011, 06:32:58 pm »
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my physics teacher says that if it doesn't tell you how many sig figs don't give more than 3 to be safe

and with 50m etc, it is 2 sig fig becuase zeros after a number matter - you give it to the least accurate piece of data (thats what we do in chem)
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