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Hamartia

Physics - Momentum etc Help Please?

Q1

You have a mass 60.0kg and are floating weightless in space. You are carrying 100 coins each of mass 0.10kg.

a) If you tthrow all the coins at once with a speed of 5.0m/s in the same direction, with what velocity will you recoil?

b) If instead, you throw the coins one at a time with a speed of 5m/s with respect to you, discuss whether your final speed will be different from before. (Use your GDC to calculate the speed in this case)

Thanks

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Well I don't wanna solve it for you so I just tried it out, pretty sure I got the right answer but I hope someone corrects me if I'm wrong :P

Anyways, since momentum is conserved (You are in space after all, just throwing coins, no external forces), you can assume:

momentum before = momentum after

Then: (p = person and c = coin, v' indicates after)

mpvp + mcvc = mpv'p + mcv'c

0 + 0 = mpv'p + mcv'c

Then you just rearrange the equation for v'p and that should be your recoil speed. Once you get that, b should be easy enough. Anyways, hope I'm right ^^'

Next time you might wanna show some working, most people won't help people that aren't willing to help themselves first by trying, I got a test tomorrow so this is a form of studying lol, otherwise I'd probably tell you to try first XD

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Well I don't wanna solve it for you so I just tried it out, pretty sure I got the right answer but I hope someone corrects me if I'm wrong :D

Anyways, since momentum is conserved (You are in space after all, just throwing coins, no external forces), you can assume:

momentum before = momentum after

Then: (p = person and c = coin, v' indicates after)

mpvp + mcvc = mpv'p + mcv'c

0 + 0 = mpv'p + mcv'c

Then you just rearrange the equation for v'p and that should be your recoil speed. Once you get that, b should be easy enough. Anyways, hope I'm right ^^'

Next time you might wanna show some working, most people won't help people that aren't willing to help themselves first by trying, I got a test tomorrow so this is a form of studying lol, otherwise I'd probably tell you to try first XD

Oh I tried alrgiht, for quite some time too.

Alright, Ill show some working next time. Thanks!!! Trying this way.

Youre using Tsokos as well?

Could you help me with problems 10, 5, 13 as well?

Been trying since I put this thread up :)

Edit: Oh and please dont tell me the answer. I wanna figure it out on my own. Hints only :P

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Ah nope sorry buddy, using Advanced Physics which isn't even an IB book but it seems really good.

Anyways, can't help you with the other problems since I don't have the book but if you figure out how to solve this one, I'll take a wild guess and say that you'll get the other ones. If not, just post your working here and someone can always point out where you got stuck :P

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