2015 LC Physics - June 15th

Broseph · 15-06-2015 07:03PM

smartz wrote: »

I said quark, because I wasn't sure if protons counted as 'fundamental' particles since they are made up of other particles.

Ahh I put down proton but you're right they're not fundamental

smartz · 15-06-2015 07:42PM

what did people get for the height of the satellite in Q6?

Broseph · 15-06-2015 07:44PM

smartz wrote: »

what did people get for the height of the satellite in Q6?

around 20.2 million metres

DarraghF197 · 15-06-2015 07:59PM

Broseph wrote: »

around 20.2 million metres

I was so surprised when I got that value. Thank God its right!

I did six questions, so I'll probably leave Particle Physics out, judging by a few mistakes I made with the fundamental particle and maybe somewhere else. All my Easter holiday break wasted to do Particle Physics and I won't even count it lol.

Chickennuggets · 15-06-2015 08:19PM

Any get the answer if the last part of q10 ? It's where u had to find the radius ?

Broseph · 15-06-2015 08:21PM

Chickennuggets wrote: »

Any get the answer if the last part of q10 ? It's where u had to find the radius ?

yeah I've some of my answers written down by the questions I got 9.16x10^-12

smartz · 15-06-2015 08:22PM

Broseph wrote: »

around 20.2 million metres

I got that as well but I thought it was ridiculous 'cause it was about 5 times the radius of the earth!

Broseph · 15-06-2015 08:23PM

DarraghF197 wrote: »

I was so surprised when I got that value. Thank God its right!

I did six questions, so I'll probably leave Particle Physics out, judging by a few mistakes I made with the fundamental particle and maybe somewhere else. All my Easter holiday break wasted to do Particle Physics and I won't even count it lol.

I didnt do the extra question in the end I just did the extra part in Q12. Hopefully it payed off because I got full marks in the ski question and did b and c too I dont know how I did in c but I did awfully bad in b lol

smartz · 15-06-2015 08:23PM

Chickennuggets wrote: »

Any get the answer if the last part of q10 ? It's where u had to find the radius ?

I got about 9mm I think.

Broseph · 15-06-2015 08:24PM

smartz wrote: »

I got about 9mm I think.

Bqv = mv^2/r ?

smartz · 15-06-2015 08:25PM

Broseph wrote: »

I didnt do the extra question in the end I just did the extra part in Q12. Hopefully it payed off because I got full marks in the ski question and did b and c too I dont know how I did in c but I did awfully bad in b lol

How did you do the last bit of the ski Q?

Broseph · 15-06-2015 08:26PM

smartz wrote: »

How did you do the last bit of the ski Q?

the force? v=u+at , let v=o and you have the time value, so acceleration = whatever value that comes out as, and fill it into f=ma, you have the mass and you can find the force

smartz · 15-06-2015 08:28PM

there was 2 different forces though. one the girl on the snow drift and the other the snowdrift on the girl.

Broseph · 15-06-2015 08:29PM

smartz wrote: »

there was 2 different forces though. one the girl on the snow drift and the other the snowdrift on the girl.

I think it's the same force (equal but opposite forces, newtons third law) thats what I said anyway could be wrong

smartz · 15-06-2015 08:33PM

Yeah I thought that at first too, but then I thought they wouldn't be that sly would they?
Anyway, I got the acceleration of the girl downhill from the first bit, used that to find her force on the snowdrift.
Then I added that to the force the snowdrift exerts in making her stop(your answer), to find the force of the snowdrift on here.
But then again, I may have massively over-complicated that.

Broseph · 15-06-2015 08:41PM

smartz wrote: »

Yeah I thought that at first too, but then I thought they wouldn't be that sly would they?
Anyway, I got the acceleration of the girl downhill from the first bit, used that to find her force on the snowdrift.
Then I added that to the force the snowdrift exerts in making her stop(your answer), to find the force of the snowdrift on here.
But then again, I may have massively over-complicated that.

ah yeah I get you, if after the 400 metres shes still going downhill you're right and if it flattens out my way is right so I'd say I assumed wrong. But you'd minus the forces not add them for your way

Chickennuggets · 15-06-2015 08:41PM

What was the answer for the last part of Q 12(d)

DarraghF197 · 15-06-2015 08:43PM

It was a weird phrasing as well. One asked what force the girl exerted and then the next part asked what is the force IIRC. I think they might have been asking for the name of the force for one of them with their awkward phrasing.

smartz · 15-06-2015 08:45PM

Chickennuggets wrote: »

What was the answer for the last part of Q 12(d)

I got 4.39x10^12

Broseph · 15-06-2015 08:47PM

smartz wrote: »

I got 4.39x10^12

Is there a marking scheme that anyone knows of?

Peregrine · 15-06-2015 08:54PM

The force she exerts on the snowdrift can be calculated by F = (her mass)(the component of her acc. due to gravity parallel to the slope calculated from the previous part)

The force the wall exerts on her is F = (her mass)(her decceleration)

Edit: Ignore this. The second part is the net force anyway and I'm still not sure about the whole method overall.

The_N4sir · 15-06-2015 08:59PM

smartz wrote: »

I got 4.39x10^12

I assume that is a typo and should be minus 12?:P

smartz · 15-06-2015 08:59PM

Nim wrote: »

The force she exerts on the snowdrift can be calculated by F = (her mass)(the component of her acc. due to gravity parallel to the slope calculated from the previous part)

The force the wall exerts on her is F = (her mass)(her decceleration)

why is the force the wall exerts on her not:
(her mass)(her decceleration) + the force she exerts on the wall.

shoopdeboop · 15-06-2015 09:06PM

The_N4sir wrote: »

I assume that is a typo and should be minus 12?:P

Was it not the amount of atoms? it would still be pretty high, no?

smartz · 15-06-2015 09:08PM

The_N4sir wrote: »

I assume that is a typo and should be minus 12?:P

no, if it was a minus it would only be a fraction of an atom.

The_N4sir · 15-06-2015 09:09PM

shoopdeboop wrote: »

Was it not the amount of atoms? it would still be pretty high, no?

Sorry I misread the post completely. Thought that was the answer to the last part of particle physics

Broseph · 15-06-2015 09:12PM

The_N4sir wrote: »

Sorry I misread the post completely. Thought that was the answer to the last part of particle physics

yeah its minus for the last part of particle physics your answers right

Cr4pSnip3r · 15-06-2015 09:22PM

smartz wrote: »

why is the force the wall exerts on her not:
(her mass)(her decceleration) + the force she exerts on the wall.

Should the two forces not be the same because of Newton's third law of motion no? lol, I just ****ted on for like 10 pages during that exam

Broseph · 15-06-2015 09:24PM

Cr4pSnip3r wrote: »

Should the two forces not be the same because of Newton's third law of motion no? lol, I just ****ted on for like 10 pages during that exam

I said the same I thought it was right at the time but now I'm not sure anyone sure of it?

smartz · 15-06-2015 09:26PM

Actually the answer for the radius in the particle physics is 9 x 10^3.
You get x10^-12 if you put in Mega Tesla instead of milli Tesla. It's a small 'm'

***2015 LC Physics - June 15th***

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2015 LC Physics - June 15th