physics mcq help needed! urgent!

[astarmathsandphysics]

thanks halosh

[halosh92]

np

[ruby92]

Q14: its B because its in equiliberium which means the triangle arrows must be head to tail like in B
Q31: R=V/I
R=row L/A
since V , L ,row are same they cancel out so we can write it like this
1/I = 1/A  (THIS IS FOR P)=1/A(THIS IS FOR Q)

FOR P:
A= pie r^2  thereofre
1/pie

FOR Q:
A=pie r^2 therefore
1/pie 4
 
we cancel out the pie this remains
P:Q
1:1/4
so P is 4 times bigger than Q so its D

20: D (brownian motion)

thnkxxxx
any ideas on 21 and 9???

[halosh92]

thnkxxxx
any ideas on 21 and 9???

we did 21 in clas...but question 9 no idea actually :S

[ruby92]

we did :s
could you explain it again please.

o/n 2004 15 37 8

[neno]

can u guys plz help me in these question
#oct/nov 2009(12)-Q14,Q27
#may/june 2009-Q11
#oct/nov2008-Q24,Q37(for 37 y do v need to noe the emf or cell 2)
#may/june 2008-Q26,Q22,Q16,Q14

[halosh92]

jun 2005
Q3
Q4 plzzz someone help 

[halosh92]

jun 2005
Q3
Q4 plzzz someone help 

could someone solve this plzz!!!!!!!!!!

[astarmathsandphysics]

o/n 2004 15 37 8
15 KE=1/2mv^2 so if v increases by factor 4 KE increases by factor 4^2
37resistance of 3-6 loop is 1/R=1/6+1/3=1/2 so R=2
resistance of 2-2 loop is 1/R=1/2+1/2=1 so R=1
more resistance in first loop so more voltage across first loop
ratio of resistance in 1st loop 1is 1:2 and ratio of resistance in 2nd loop is 1:1 so I_1>I-2

8 C the distance is increasing but the car is slowing down

[astarmathsandphysics]

un 2005
Q3
Q4 plzzz someone help
3 speed is d/t=100/10=10m/s
1/2mv^2=1/2*80*10^2=4000J
4 error in 2.5=2% error in 40=0.25%
sum of errors=2.25%
40/2.5=16 +-2.25%=16+-0.36
I think they do this wroong

[astarmathsandphysics]

#oct/nov 2009(12)-Q14,Q27
14 conservation of momentum
o=-2*2+1v so v=4
1/2mv^2 for both
1/2*2*2^2 +1/2*1*4^2=4+8=12
27 mg=Eq so q/m=g/E and charge must be negative since the drop is attracted to the positive plate

[astarmathsandphysics]

#may/june 2009-Q11
pressure depends on depth increasing with depth
S=Q and R>P since s and q are at same depth and R is deeper than P

[ruby92]

M/j 2004
9
25(point p with zero displacement be stationary?)

[astarmathsandphysics]

#oct/nov2008-Q24,Q37(for 37 y do v need to noe the emf or cell 2)
24   3 times the frequency cos 3 little waves in the space of 1 big wave and half the amplitude
37  the emf of cell 2 will be the voltage across XT so voltage per unit length=E_2/XT

[astarmathsandphysics]

#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