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# TSR Physics Society watch

1. (Original post by Clara_H4)
Just heard woman on TV programme about Titan (Saturn's moon) say she didn't want "nuclear" stuff in space.
Indeed that was very funny/hilarious to watch, if not to hide my blood boiling at their idiocy. What a fantastic documentary though - I just flicked onto it at the very start, not expecting much, but was blown away. The capacity for human ingenuity really is amazing!

The soundtrack was also, one of the most beautiful I think I've ever heard on a BBC documentary. Wish I knew what some of the pieces/songs were called

2. EDIT: from here
3. Haha that's awesome.

Btw anyone heard the latest from CERN, clocked subatomic particles traveling faster than light, kinda hope the results are confirmed, would be mind blowing
5. (Original post by Mind Tool)

Btw anyone heard the latest from CERN, clocked subatomic particles traveling faster than light, kinda hope the results are confirmed, would be mind blowing
Yeah, but then we would have to rewrite almost all of Physics!
6. A bit more basic humour than the last one, but more SMBC:

7. Hi guys!

Could you help me with this question? I need the explanation.

A train consists of a powered engine pulling two unpowered carriages.

The engine has a mass of 20000kg, and each carriage has a mass of 5000kg. When the engine
accelerates from rest it develops a thrust (driving force) of 15000N.
Ignoring resistive forces, what is the tension (pulling force) T in the coupling between carriage 1 and
carriage 2?

A 2500N
B 3750N
C 5000N
D 7500N
E 15000N
8. Hi guys,
I've got a question to do with physics. It's not related to the syllabus, but I can't really think where to put it otherwise, and internet searching has been of little help.
My question is this: are virtual particles affected by gravity?
The thing is, so far as i can work out, if virtual particles aren't affected by gravity then that basically throws a spanner in my understanding of gravity. I could explain exactly why, but it would be difficult and frankly I'm no physicist, and I'm fairly certain that i'm just missing out on some major basic principle that would make everything make sense.
I asked my physics teacher but he essentially ducked the question: I suspect he doesn't really know. I was under the impression that virtual particles AREN'T affected by gravity, but I dont really know where i got this from.
9. Hi

Can any1 get me the OCR gcse physics P7 June 2011 higher question paper?
10. Hi guys,
I was having trouble getting the right answers to a particular question about charging capacitors.
Would appreciate it if any of you could help. The question is this:

A 50µF capacitor is being charged from a 6V battery via a 100kOhm resistor. What is the initial charging current? After a period of time the charging current is 30µA. What are the p.d.s across the resistor and the capacitor at that moment? How much charge has been stored on the capacitor up to this time?

Attempt:
Initial charging current = E/R = 6/100000 = 60µA

And the rest I was having trouble with.
I used IR=V------(30x10^-6)(100000) = 3V
But what I dont get is how can you find the p.d.s across the capacitor and resistor? I just found V but I dont know what that V is of..

And the main problem is the last part...the answer in the book is 6µC but no matter which equations or graphs I use- I keep getting 1.5x10^-4 C...how can you get 6?
11. (Original post by Alwin77)
Hi guys,
I was having trouble getting the right answers to a particular question about charging capacitors.
Would appreciate it if any of you could help. The question is this:

A 50µF capacitor is being charged from a 6V battery via a 100kOhm resistor. What is the initial charging current? After a period of time the charging current is 30µA. What are the p.d.s across the resistor and the capacitor at that moment? How much charge has been stored on the capacitor up to this time?

Attempt:
Initial charging current = E/R = 6/100000 = 60µA

And the rest I was having trouble with.
I used IR=V------(30x10^-6)(100000) = 3V
But what I dont get is how can you find the p.d.s across the capacitor and resistor? I just found V but I dont know what that V is of..

And the main problem is the last part...the answer in the book is 6µC but no matter which equations or graphs I use- I keep getting 1.5x10^-4 C...how can you get 6?
Because the total current is 30µA, the total voltage in the circuit must be sufficient for this to be the case, so applying V=IR, V=3v, where V is the total voltage in the circuit.

Because the resistor is a component of the circuit with a 30µA current flowing through it, the total voltage must correspond to the voltage across the resistor.

The current reduces from its intitial value as the capacitor becomes charged because this process sets up an opposing voltage from the capacitor relative to the battery, reducing the total voltage.

I.e Vtotal = Battery V - Cap V
so 3=6-cap V.
Therefore cap v = 3v.
(In this case both capacitor voltage and total voltage happen to be equal).

Hope this helps
12. (Original post by hungryaardvark)
Hi guys,
I've got a question to do with physics. It's not related to the syllabus, but I can't really think where to put it otherwise, and internet searching has been of little help.
My question is this: are virtual particles affected by gravity?
The thing is, so far as i can work out, if virtual particles aren't affected by gravity then that basically throws a spanner in my understanding of gravity. I could explain exactly why, but it would be difficult and frankly I'm no physicist, and I'm fairly certain that i'm just missing out on some major basic principle that would make everything make sense.
I asked my physics teacher but he essentially ducked the question: I suspect he doesn't really know. I was under the impression that virtual particles AREN'T affected by gravity, but I dont really know where i got this from.
The term "virtual" only tells us that the particle exists for a limited time and space. The term often implies the particle is bosonic in nature, the common examples of which are the gauge bosons ("force carriers"). These include: photons, W-, W+ and gluons.
Photons have zero rest mass and in that state of energy are not affected by gravity, However W bosons are much more massive and as a result of possessing a rest mass will certainly be affected by the gravitational force but remember the kind of time scale and distances we are talking about its effects are certainly negligible.
13. (Original post by Hulksmash)
The term "virtual" only tells us that the particle exists for a limited time and space. The term often implies the particle is bosonic in nature, the common examples of which are the gauge bosons ("force carriers"). These include: photons, W-, W+ and gluons.
Photons have zero rest mass and in that state of energy are not affected by gravity, However W bosons are much more massive and as a result of possessing a rest mass will certainly be affected by the gravitational force but remember the kind of time scale and distances we are talking about its effects are certainly negligible.
Off topic: Can something with zero rest mass exist? I mean, I'm aware of the fact that photons have mass by virtue of their energy when they're moving, hence they're affected by gravity. But how can something exist without mass? I'm assuming the answer is that photons cannot exist as stationary particles IE they have to be on the move. Any insight would be appreciated.
14. Hey y'all, I was wondering if/how I could join?

I find physics the most interesting out of the alevels I've chosen, I've just done my unit 1 exam and have started unit 2.
15. Could anybody explain the differences between Physics A and B for AQA Physics at A-Level ? I haven't been able to get my hands on the B textbook and I'm just curious.
16. (Original post by #Bi-Winning)
Hey y'all, I was wondering if/how I could join?

I find physics the most interesting out of the alevels I've chosen, I've just done my unit 1 exam and have started unit 2.
You can join here: http://www.thestudentroom.co.uk/group.php?groupid=248
17. Hello there. I'm a mature student studying GCSE Physics at college.

May I join this fine society?
18. (Original post by 21stcenturyphantom)
Hello there. I'm a mature student studying GCSE Physics at college.

May I join this fine society?

19. (Original post by boromir9111)

Done, wahoo! Physics exam tomorrow! That's my Unit 1 work out of the way, then onwards to Unit 2 - Motion, Energy & Momentum! I'm very glad, learning about wind turbines was getting rather boring.

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