Author Topic: physics  (Read 17913 times)

Offline halosh92

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Re: physics
« Reply #75 on: April 20, 2010, 11:35:15 am »
i found this in the syllabus:
-''Show an understanding of the origin of the upthrust acting
on a body in a fluid''

what does that mean???

-''Recognise that, for a perfectly elastic collision, the relative
speed of approach is equal to the relative speed of
separation''

and could someone briefly explain this and give an example, how are the questions diiferent from the normal m1u1 +m2u2=m1v1 + m2v2
??????? :-[ :-\
everyday we wake up is a miracle, then how do we say miracles dont happen?????

Offline astarmathsandphysics

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Re: physics
« Reply #76 on: April 20, 2010, 11:42:02 am »
The first one is Archimedes principle. The upthrust is equal to the weight of fluid displaced and for the second one mass is not involved.  http://www.astarmathsandphysics.com/a_level_maths_notes/M2/a_level_maths_notes_m2_restitution_momentum_collisions.html

Offline ruby92

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Re: physics
« Reply #77 on: April 20, 2010, 05:39:51 pm »
but the As syllabus doesn't include the restitution principle
V of approach=V of seperation..so v1+u1=v2+u2

Offline ruby92

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Re: physics
« Reply #78 on: April 20, 2010, 07:32:10 pm »
the ultimate tensile stress is a point before the fracture/breaking point.where the materia "gives" or "yields'??
is this right?

Offline Saladin

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Re: physics
« Reply #79 on: April 20, 2010, 08:08:43 pm »
Yes, that is right.

Amr Fouad

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Re: physics
« Reply #80 on: April 20, 2010, 09:35:14 pm »
the ultimate tensile stress is a point before the fracture/breaking point.where the materia "gives" or "yields'??
is this right?

nope..only the first part is right..UTS is NOT the yield point..the yield point is the point where plastic deformation starts...UTS is simply the stress where the material breaks..

Offline ruby92

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Re: physics
« Reply #81 on: April 23, 2010, 05:50:32 pm »
what wld a displacement position graph for a longitudnal wave look like?
if anyone has notes on superposition and resonance particularly explaining the wavelenght and lenght if you could post it here it wld be realli helpful  :)

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Re: physics
« Reply #82 on: April 23, 2010, 06:00:47 pm »
what wld a displacement position graph for a longitudnal wave look like?
if anyone has notes on superposition and resonance particularly explaining the wavelenght and lenght if you could post it here it wld be realli helpful  :)

Graph is an exact duplicate of the one for transverse wave

Notes: http://www.s-cool.co.uk/alevel/physics.html   go to oscillations and waves part

Offline ruby92

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Re: physics
« Reply #83 on: April 24, 2010, 04:17:41 pm »
@A.F ; it doesn't have much on resonance  ???

O/N 2001 paper1
Q 2 and 15

Offline astarmathsandphysics

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Re: physics
« Reply #84 on: April 24, 2010, 08:14:01 pm »
2 hours

Offline ruby92

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Re: physics
« Reply #85 on: April 24, 2010, 08:41:24 pm »
okie...
i also have a doubt in M/J 2002 paper 1
2,15,26,28,35

Offline astarmathsandphysics

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Re: physics
« Reply #86 on: April 24, 2010, 09:30:56 pm »
Shortly

Offline astarmathsandphysics

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Re: physics
« Reply #87 on: April 24, 2010, 11:02:19 pm »
I dont habve o/n 2001 p1
mj 02
q2. B cos x+-y=z
15.d cos resulta of 3 and 4 is 5 to upper right
26. 1 period=4 squares =4*2ms=8ms
1/8ms=125Hz B
28. path difference =1/2 wavelength C
35.resistance in ratio of voltages accros resistance 2:1:2 C

Offline ruby92

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Re: physics
« Reply #88 on: April 26, 2010, 05:20:05 pm »
2.why not A? how do we know the direction of the resultant force?
could you please explain Q's 15 and 35 in more detail

Also o/n 2002 paper 1; 36
« Last Edit: April 26, 2010, 06:41:35 pm by ruby92 »

Offline halosh92

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Re: physics
« Reply #89 on: April 26, 2010, 06:18:51 pm »
could someone explain q3b
i dont get it , dont we have to use the fdsin thita formula here..shouldnt the distance be perpendicular to the force..
in the ms..they multiplied the distance (in the direction of X) by X
??????????????????URGENT
thx
everyday we wake up is a miracle, then how do we say miracles dont happen?????