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Year 12s: what will be the first way you research your future options? >>

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Reply 20

bruceleej

sohanshah

so the 3 i get are:

u1-v1=e(V-u)

V+u=v1+u1

I=mu1-mu

is this right???

Yes thats right, now time for some algebra. Eliminate v1 and u1

lol tht is difficult

lol are you sure these equations are correct because I get something humongous:

2I=[(e(V-u)+V+u)m]/2mu

Reply 23

bruceleej

Lol, easiest way is to sub for V1 using the first one into the second.
You should get

Spoiler

.
Then sub for u1 using the momentum equation into the equation you get from doing the above.

Reply 24

bruceleej

sohanshah

lol are you sure these equations are correct because I get something humongous:

2I=[(e(V-u)+V+u)m]/2mu

You must have made a slight mistake somewhere.

Reply 25

Kyalimers

I'm a -u out in the brackets - (so close yet so far)

I have

I= 0.5m(V+u+e(V-u)-u)

It should be....

I= 0.5m(V+u+e(V-u)-2u)

Reply 26

Kyalimers

got it - thankyou so much bruceleej

You are a legend - I will rep you as much as poss over next week lol - please remind me to as well - you deserve it...

Its cool

Now for question 8, Im still trying to eliminate the v1's and the v2's..lol...So I will get back to you on that one cant see a nice way to do it yet{but I think using the difference of 2 squares somewhere in the Loss in KE equation might help to split the terms}.Hmm lets see.

Reply 29

Kyalimers

lol im waiting........ lol joking
Leave it if u cnt do it - uve done enough lol

I get upto

2E=m1u1^2+m2u2^2-m1v1^2-m2v2^2

and

v2-v1=e(u1-u2)

BTW YOU ARE VERY VERY VERY CLEVER... u at uni doing maths???? (take it as a compliment please-no offence intended)

Reply 30

bruceleej

Why, thank you. Ohh and No Im not doing maths at Uni. Im on a gap year gonna do Electronic & Electrical Eng next academic yr.

Reply 31

Kyalimers

Wow cool. I wish one day I can do maths like you can

Unfortunately I'll be dead by then or I'll be studying all day every day for a hundred years :frown:

lol

Reply 32

Kyalimers

i found the third eq. i think: u1m1+u2m2=v1m1+v2m2

ohh yea thats right.

algebra again lol

I reckon I'll challenge my teacher to simultaneously solve these 3 lol

Thanks so much again

Without you today i would have died

Reply 36

bruceleej

sohanshah

I reckon I'll challenge my teacher to simultaneously solve these 3 lol

Thanks so much again

Without you today i would have died

Lol, that should be quite interesting..Thats if he hadnt done so in the past and has a little note somewhere with the solutions.

But anyway, I managed to complete 8;

Spoiler

Reply 37

Kyalimers

wow bruceleej lol Thats quite something. U r amazing lol - I must have kept u busy doin that q lol

Thnx

Reply 38

Kyalimers

I understand hardly any of it lol

I lose you nearly immediately after you start subbing the 3 equations lol

But maybe I can maintain some pride after having seen my teacher do this inside 7 minutes :frown:

flat. he showed us not the working lol as he thinks this is a capable challenge for a 15 yr old..... hahah lol thankyou so much