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Physics 1 and 2 Edexcel

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MichailZ

Ah, the key is to read the question. It said in the question that one of the axels on one troley produces this frictional force, and it is the only one acting on the trolley-system. The other axels are therefore smooth...

Michail

noooooooooooooooo i did 3x0.36n dam it

Reply 61

mace5000

Tha Blacksta

i found it was quite easy because there was soo many 'show that its approximately' questions n when you arrive at an answer very close you know its all looking good. Rushed the first half a bit though: Some of my answers where...
Work Done
Acceleration
Velocity
Impulse
The height for the track was 0.82m
speed=1.33
time=2.66
wasnt 3rd law because not 2 distinct bodies, and not opposite directions,
all quite similar stuff to futureaussiecto, be dissapointed with anythingn less then an A as i thought it was a reasonably nice paper.
All the prove that stuff i got an answer pretty close 2 apart from the stool when it said about 11N i got 9.33N not sure if that's close enough realy? What everyone else get? and what did every calculate that the NewtonMetre should read? and the contact force?

for the newton thrid law pair, i put acts on different bodies and is not the same type of force i.e one was gravational and the other was contact.

Reply 62

=Keith=

For the homogenous related question

the lh.s was I the unit has to be Cs^-1 because Q = I * T so I = Q/t which is Cs^-1
and the other reason is that this way it even satisfys the equation.

Reply 63

mace5000

noooooooooooooooo i did 3x0.36n dam it

a thought just occured to me, solids transmit forces right? and since the trollies were towed together the force must be transmited.
just a thought...

Reply 64

Jean

isn't an equation homogenous because both sides have the same units? so all we have to do is to check for the units at both sides?

Reply 65

lookenneth

ya both sides have same units so they're homogeneous right? That's how I was taught.

Reply 66

mace5000

[QUOTE="Jean"]

isn't an equation homogenous because both sides have the same units? so all we have to do is to check for the units at both sides?

yes thats right. and in the question both sides did have the same units.

Reply 67

futureaussiecto

mace5000

a thought just occured to me, solids transmit forces right? and since the trollies were towed together the force must be transmited.
just a thought...

If there was a force acting on it, odds are it was greater than the frictional force of 0.12N, which would acceleration, which would mean it cant be slowing down>>>>>> only force acting was friction.........

Reply 68

Euniceee

I think da paper is much harder than I thought...haaa...nwayz..it's over now I will have to start my revision on Phy 4 now..=) anyone takin phy 4 on fri?

Reply 69

Justintabib

I found phy1 very easy compared to other papers.There were a lot of 'show that' questions & I could cope up well with them :smile:

there were less descriptive real-life questions such as relating principle of moments to ballet dancer (i remember doing it!) or archimedes' comments to practical world! Was in a wonderful mood after finishing unit 1 but unit 2 was worse thasn i expected.I knew it'd be tougher than June 05 (that was pretty simple) but the suggestions & explanations especially related to electricity problems just disguested me totally.I've chosen Medical Physics for topics option in unit 3 & that elution graph has cost me 3-4 marks :frown:

i thought so much details about elution is not in the syllabus (the modular book has got no graph for elution cell or anything related to the graph,it only has some descpition about what happens inside elution cell. I expected gamma camera to show up this time...it has been quite long since we've had it & was well prepared for it, but it didnt come! :frown:

for those who wants to give medical in may 06, i suggest u study gamma camera well before the exam because it's higly likely that its gonna come next time.

Reply 70

Justintabib

futureaussiecto

PHY2

for twisted thermistor i said the cross sectional area would be reduced- reducing the current

for emf, voltage across battery was like 5.8 summin i think

emf is the work done per unit charge across the whole circuit AND batter/power supply, otherwise it'd be the pd.

For last part of #1,I said for twisted nails or whatever it was, resistance would increase (more opposition to flow of electrons through a twisting body) so total R in circuit increases (series circuit) hence current I would decrease.I'm not sure about it because I've heard a lot of other students saying R would be the same since R=(resistivityxlength)/area & the twisted thing was made of the same material (same rho) & it was identical (so same A & l).twisted does not mean length has increased or decreased & since R only depends on those, R & hence current would be the same! but what about more no. of collisions to resist flow of charge?? i hope i'd score something out of 3!
for identical battery connected in parallel to the existing one, I said emf would be the same (p.d. same for parallel circuit), total internal resistance r would decrease (resistors in parallel) so total R in circuit would decrease & therefore current I in circuit increases.since V (terminal p.d)=E - Ir , E same,I increase & r decrease, so V would be the same when switch is kept closed.
after i got home, i did some calculations to verify my answer.fixed R was 10 ohm in series & internal r for each battery was 0.4 ohm so total R becomes 10+(0.4/2)=10.2 ohm. emf of each battery E=6 so current= E/total R = 6/10.2=0.59 A (it was 0.58 A without battery in parallel).so new V comes out to be V=6 - 0.58x0.2 (r=0.4/2) = 5.9 V. Initially it was 5.8 V calculated in earlier part hence V has actually increased by 0.1 V!!! I didnt get time to do the calculations during my exam & honestly, didnt bother to do for a theoretical answer!so i guess i might lose a mark here for stating p.d would be the same,even though it essentially remains the same!keeping my fingers crossed!!

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.x.g.x.

how did you get 11.4?

I also got 11.4 N.Intitially I got 9.33 N like u people but i spent a lot of time in that question at the end to finally get 11.4 which is appox. 11 N. I cant remember now how i got 11.4N, but there was a very cunning trick i remember. :cool: