Physics Aftermath

JC 2K3

Fobia wrote:

1/f = 1/v + 1/u. Some quick maths gives you 1/f = (v + u)/vu, invert and you have f = vu / v+u. So pop the vu on the Y axis, v + u on the X axis for your straight line through the origin. Then the slope of this is the focal length. Doubt any one of ye care any more though

My friend did that, very smart

microbiek

why does the sphere ocillate with harmonic motion?? because its attached to a spring etc???

Kwekubo

mathew wrote:

I thought it was to do with the nutrino. I know Pauli discovered it, but did Fermi propose it, or something...

That's it, yeah - Fermi proposed that a small particle was given out when Beta decay happens and Pauli named it.

JC 2K3

ZorbaTehZ wrote:

Q8 Ok question, never seen Butterfly Net Experiment on a paper though, so I'm not sure if my diagram was great. I kinda just slopped through the arithmetic here (found it hard to focus for some reason), I took the charge to be concentrated at its center. I thought comparing 4C with 5uC was kind of off-putting.

I got confused there, because the charge is supposed to be on the outside of the dome and the gave the diameter....

I took d = 0.07....

microbiek

JC 2K3 wrote:

My friend did that, very smart

no thats wrong i hope because they have to cut the axis like make a triangle with the axiseseseses

madnirvana

microbiek wrote:

why does the sphere ocillate with harmonic motion?? because its attached to a spring etc???

damn i never though of the spring:mad:

i wrote that the acceleration is proportional to displacement and always directed towards that point.

urs sound right

JC 2K3

microbiek wrote:

why does the sphere ocillate with harmonic motion?? because its attached to a spring etc???

The spring obeys Hookes law and the sphere is attached to it.

Therefore F = -ks
ma = -ks
a is proportional to s
therefore, SHM.

That's what I got anyway...

Turnip2000

DtotheK wrote:

I thought a watt was joule per second and they said today as in just in general , nowadays, 300G joules are produced per second.

I just multiplied their thing by 60 for a minute..

What did others do?????

I went with 300Gw a day ...devided by 24 den 60 to get how much per minute?
I thought it was right at the time??

microbiek

madnirvana wrote:

damn i never though of the spring:mad:

i wrote that the acceleration is proportional to displacement and always directed towards that point.

urs sound right

yeah then i said that because it is attached to a spring it obeys hookes law but im not sure i hated that test because for every answer i wasnt sure if it was def rite

DtotheK

i wrote cause it fits the forluma

a = - (omega)^2 X (which i didn't get it in the form.. had to twist it around )


and then cause it's accel is dir. porp. to its distance from the po of Eq.
and it's accel is always directed towards that pt... or something like that

microbiek

JC 2K3 wrote:

The spring obeys Hookes law and the sphere is attached to it.

Therefore F = -ks
ma = -ks
a is proportional to s
therefore, SHM.

That's what I got anyway...

ah yeah but they just asked you to derive that so i tot they were looking for something else

ZorbaTehZ

microbiek wrote:

no thats wrong i hope because they have to cut the axis like make a triangle with the axiseseseses

Apparently what you are supposed to do is get all the values for 1/u and 1/v, and then make a graph with two lines on it. One line is the values of 1/u with v and the other is 1/v with u, and the place they cross is 2f. Bit gammy tbh.

JC 2K3

microbiek wrote:

no thats wrong i hope because they have to cut the axis like make a triangle with the axiseseseses

There is always more than one answer to a question

In any case, I just took the two furthest apart points given and got the average f from them.....

Naikon

I thought the Higher paper was more obscure than usual.
Q2 was a joke:(

carlowboy

JC 2K3 wrote:

The spring obeys Hookes law and the sphere is attached to it.

Therefore F = -ks
ma = -ks
a is proportional to s
therefore, SHM.

That's what I got anyway...

Looks like I didn't do too bad in that question then!

JC 2K3

Turnip2000 wrote:

I went with 300Gw a day ...devided by 24 den 60 to get how much per minute?
I thought it was right at the time??

I took it as being per year and got it wrong, but if you think about it, Watts is joules per second and therefore you multiply it by 60 to get joules per minute.

eZe^

Turnip2000 wrote:

I went with 300Gw a day ...devided by 24 den 60 to get how much per minute?
I thought it was right at the time??

But 1 Watt = 1 Joule/sec... not 1 Joule/day

Youd be right if it said it supplies 300GJ per day.

madnirvana

anyone got the answer for

10 a i???

i get like 11580473 m/s

microbiek

what did people get for -k in Q6 and max acceleration i got for -k=39.45 and max acc.=115 both wrong??

madnirvana

microbiek wrote:

what did people get for -k in Q6 and max acceleration i got for -k=39.45 and max acc.=115 both wrong??

i got w = 115

and k = 39.45

ZorbaTehZ

microbiek wrote:

what did people get for -k in Q6 and max acceleration i got for -k=39.45 and max acc.=115 both wrong??

Max acceleration 115 ?! I got 2.8 or something like that, and I got te same value for k.
What about the age on question 12D, I got 2 half-lives. Something like 11000 years iirc.

microbiek

ZorbaTehZ wrote:

Max acceleration 115 ?! I got 2.8 or something like that, and I got te same value for k.
What about the age on question 12D, I got 2 half-lives. Something like 11000 years iirc.

ye correct i said 3 by mistake wasnt thinking!!!!

ZorbaTehZ

madnirvana wrote:

i got w = 115

and k = 39.45

Was omega not root of 115.

microbiek

ZorbaTehZ wrote:

Was omega not root of 115.

were talkin bout Q6



and good some1 else got the same answers!!! They seem huge

adam_ccfc

JC 2K3 wrote:

It was a hard paper. Q2 was a disgrace. I know I used a electricity and a fúcking Joulemeter when doing that experiment and last time I checked the syllabus, you were allowed use and learn either method

Spot on, they went against the syllabus with that question. Outageous.

Overall, it's hard to say. I wanted an A1, it'll be tight.

ZorbaTehZ

microbiek wrote:

were talkin bout Q6



and good some1 else got the same answers!!! They seem huge

Uhmm, yes I know. That w thing is a small omega.

madnirvana

microbiek wrote:

were talkin bout Q6



and good some1 else got the same answers!!! They seem huge

no i got w= 115

w^2 = i duno

WELL u know wat forget it!!!!:mad:

whats done cannot be done..Damn it!! shakespear is over aswell:D

Nehpets

JC 2K3 wrote:

I took it as being per year and got it wrong, but if you think about it, Watts is joules per second and therefore you multiply it by 60 to get joules per minute.

**** I divided the 300x10^9 by (24)(60)

DtotheK

my omega = 32 ...pretty certain it's wrong tho.

my K is what you are all gettin 39.somethin..


madnirvana i see you want that answer pretty badly!! i threw out my paper and dont even know the question so sorry!

microbiek

what application could you give for all the charge residing on the outside of a conductor??? and why does it do it theres no explanation in the book! is faraday cage an explanation