physics mcq help needed! urgent!

[ifraha18]

ok c over all its 5V the first resistor gets 2 volts, the second gets 1 volts, the 3rd gets 2volts also
so the 1st and 2nd resistors have same voltage, and same resistances
got it?

oo Thanks..yea...

[ifraha18]

q35 nov 2002.??

[halosh92]

q35 nov 2002.??

when u increase the resistance in the variable resistor, voltage increases

voltage then DECREASES in the wire

then
R is directly proportional to length "L"
when resistance of variable increases then the length has to increase...thus it moves to Y

[astarmathsandphysics]

D since more of the pd will be accorss the variable resistor
We need to increase the pd across the wire bey increasing its resistance, hence its length

[halosh92]

10) momentum is conserved, take momentum for each side seperately
2m will have speed u
and m will have speed 2u, so that the product of both equations will give 2mu(same momentum)
ke
x= (2u)² y=(u)²
so dividin both will give 4u/u which is 4/1

By the way the answer is wrong
its supposed to be : 2
u have to use (ke) formula here so the 4 and 2 cancel each other when u do the calculations.

[neno]

#may/june 2008-Q26,Q22,Q16,Q14
26 twice as far so 1/2^2 =1/4 the intensity
27 D the wavelength is 4 x distance to wall cos node to antinode is 1/4 wavelength
22 c not elastic cos is deforming
14 A take moments about top of ladder against wall
16 A moves in direction of the force distance s so W=Fs
A

but the answer for 22 in the marking schemes is B for 22 thts wat i dont get

[astarmathsandphysics]

Platic but not elastic - ot will not return to it's original length when the force is removed

[neno]

i understand wat u r sayin but its rong the correct answer it says is B elastic but not plastic

[ifraha18]

it retrns to the same original length!!!dt means it is elastic the question says dt ot follows the same force extension curve when contracted

[neno]

its cannot be plastic cuz in the question it says "metal" and also if a plastic crosses its elastic limit it shatters or breaks cuz it brittle

[ifraha18]

if it ws plastic den it wont follow the same force extension curve when contracted

[ifraha18]

q14 ,30,34 and 16 june 2008..??plz explain in detail

[neno]

ooohhh so cuz it has the same graph when contracted n when stretched it is elastic ...so incase of a plastic how wud the graph be wud it be straight after the elastic limit the line will stop and both the contracting and stretching  graphs will be different im i ryt??and it will be a curve not a straight line..

[ifraha18]

if it was plastic den the curve wont follow the same line when contrcted..some work wil be lost!!!

[astarmathsandphysics]

exactly