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

Broseph

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

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

Broseph

smartz wrote: »

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

around 20.2 million metres

DarraghF197

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

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

Broseph

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

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

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

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

smartz wrote: »

I got about 9mm I think.

Bqv = mv^2/r ?

smartz

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

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

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

Broseph

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

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

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

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

DarraghF197

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

Chickennuggets wrote: »

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

I got 4.39x10^12

Broseph

smartz wrote: »

I got 4.39x10^12

Is there a marking scheme that anyone knows of?

Peregrine

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

smartz wrote: »

I got 4.39x10^12

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

smartz

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

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

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

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

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

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

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

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'