Edexcel Unit 4: Physics on the Move 6PH04 (11th June 2015)

Original post by johntoby

I got 3s for the roundabout, and that mass didn't change it, anyone? Can someone explain that one asking for the capacitor time to lose half energy and half its charge? That was the only one I was unsure of

I got the same for the roundabout

See above for my explanation on the capacitor question.

Tell me what you think thanks

Reply 442

OP

Original post by ertuu

Yes. You are right. The units in particle physics are such that a rest mass of 10 eV/c^2 means that the particle has an energy of 10 eV and also a momentum of 10 eV/c. The values are all interchangeable. The June 2012 paper had a good question on this.

So glad this didnt come up bc I didnt see your reply before the exam haha. I still don't understand why that is, but who cares anymore hahah

Reply 443

chermaine123

2

Original post by MangleKuo

I wrote less.

Because E=1/2 Q²/C and C is constant
Hence E = kQ²
for E become 1/2 E
Q need to become 1/√2 Q
1/√2 ≈ 0.7
Q reaches 0.7Q₀ before reaching 0.5Q₀
So the time is less

I wrote the other way round
but I use the correct equation, will I be able to get 1 mark?

Reply 444

username1162972

18

Boundaries?

Posted from TSR Mobile

Reply 445

OP

Original post by Nick.p97

On the gce paper were we supposed to use 3.3 or 6.6 for the charge on the capacitor??

I used 6.6 but really not sure :/ If it's wrong that's so many marks lost :'(

Reply 446

username1162972

18

Original post by cerlohee

I used 6.6 but really not sure :/ If it's wrong that's so many marks lost :'(

Inused that aswellz
I dropped stupid marks.

Posted from TSR Mobile

Reply 447

jay_em

2

Man, I said momentum not conserved because of the chemical energy explosion...

Reply 448

iceangel8

14

Original post by cerlohee

I used 6.6 but really not sure :/ If it's wrong that's so many marks lost :'(

You will definitely get some ecf I wouldn't worry it was a straight out trick question which threw me a bit at first but I think it was just 3.3 as one plate had a deficiency of 3.3 and the other one had accumulated 3.3 as charge moves from one to the other.

Reply 449

OP

Original post by The Best1

yeah i just remember putting 7s, dont remember what decimal points, 7.08 sounds like what i put!

I put that too :smile:

Reply 450

Nick.p97

anyone else get 4.1A for the max charge on that ring question??

Reply 451

iceangel8

14

Did Jan 2014 IAL just yesterday with the situation of a magnet oscillating in a coil which was good :smile:

I wasn't really sure if I answered the question I firstly talked about emf being induced when it enters and leaves but when stationary it isn't (relating to change in flux) so emf varies creating an alternating current of the same frequency of the oscillations???

Reply 452

johntoby

4

The 6 marker about the rocket, I put that Ek wasn't conserved because there was an explosion so some chemical energy to kinetic. May be wrong because it said it was empty, but there must be fuel for an explosion. Total energy and momentum conserved, speed of probe increases because relative momentum of the tank is negative. Thoughts?

Reply 453

iceangel8

14

Original post by Nick.p97

anyone else get 4.1A for the max charge on that ring question??

Yep got that! Nice juicy maths question :3 threw me at first with the Ts^-1 unit!

Reply 454

johntoby

4

Original post by Nick.p97

anyone else get 4.1A for the max charge on that ring question??

Yeah I think so

Reply 455

OP

I have a really bad memory but could we try to compile a list of all the questions to make an unofficial markscheme and I'll add it to the original post.

For the momentum one, did people put that the increase in KE had to be due to chemical converstion to kinetic energy in the shuttle? Or am I jsut getting my markschemes muddled up lool

Reply 456

Destrian

2

Original post by johntoby

The 6 marker about the rocket, I put that Ek wasn't conserved because there was an explosion so some chemical energy to kinetic. May be wrong because it said it was empty, but there must be fuel for an explosion. Total energy and momentum conserved, speed of probe increases because relative momentum of the tank is negative. Thoughts?

This is what I thought would happen, but I didn't write it very concisely.

Reply 457

MangleKuo

Original post by chermaine123

I wrote the other way round
but I use the correct equation, will I be able to get 1 mark?

I think so. One mark for equation one mark for answer probably.

Reply 458

johntoby

4

Original post by cerlohee

I have a really bad memory but could we try to compile a list of all the questions to make an unofficial markscheme and I'll add it to the original post.

For the momentum one, did people put that the increase in KE had to be due to chemical converstion to kinetic energy in the shuttle? Or am I jsut getting my markschemes muddled up lool

Yeah I got that, but I'm a little uneasy about it because it said the tank was empty... But surely you need fuel for an explosion so it must be from elsewhere

Reply 459

Nick.p97