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physics

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nid404:

--- Quote from: Phosu on May 07, 2010, 06:36:16 pm ---got it Thanks!

more questions!
Nov 02 pp1
9, 11, 12, 14, 17, 28, 36


--- End quote ---


Q12) 60m-30m= 2mv
        30m=2mv
           v=15cm/s
Q14) 50x +100X10= 20X60
             50x=200
                x=4cm

+4cm from the pivot=44cm

Q17) no change in k.e because velocity is constant

Q28 and 36 I've also explained this elsewhere...will look





        

        

halosh92:

--- Quote from: Phosu on May 07, 2010, 06:36:16 pm ---got it Thanks!

more questions!
Nov 02 pp1
9, 11, 12, 14, 17, 28, 36


--- End quote ---

14) 50g is on the other side
therefore clockwise = anticlockwise     let z be the unknown distance so:
(20g * 60/100) + ( 100g * 10/100) = (50g * z)
g=9.8 and convert cm to m
so z=44 cm

17) constant speed , kinetic energy= 1/2mv^2
no change in velocity so no chang ein kiinetic energy therfore change=0

28) lamda = ax/D
increase lambda , increase x

36) find current first so:
first loop and 2nd loop total resistance (15*15/15+15) =7.5
so total resistance = 7.5
total Voltage = 2V
R=V/I
I=2/7.5 =0.2666666
THATS TOTAL CURRENT.......current in one loop divide by 2 = 0.133333
so IR=V
0.1333 * 5 =0.6666
and  check the choices 2/3= 0.666666
so its A

halosh92:

--- Quote from: nid404 on May 07, 2010, 07:00:09 pm ---
Q12) 60m-30m= 2mv
        30m=2mv
           v=15cm/s
Q14) 50x +100X10= 20X60
             50x=200
                x=4cm

+4cm from the pivot=44cm

Q17) no change in k.e because velocity is constant

Q28 and 36 I've also explained this elsewhere...will look



i already did nid :)

        

        


--- End quote ---

nid404:
oh gr8 thanks  ;)

Phosu:

--- Quote from: halosh92 on May 07, 2010, 06:51:45 pm ---11) speed of approach=speed of separation
uA - uB = vA - vB
different directions lets take this direction -----------> as (+)
so
uA-(-uB)=vA + vB

--- End quote ---

could you plz explain the difference between speed of approach and speed of seperation. how do we know that they are same?
wen and how can we use this formula? and why cant we just use m1u1+m2u2=m1v1+m2v2

plus wen u solve the ans u've given, it gives uA+uB=vA+vB but the mark scheme says its uA+uB=vA-vB


--- Quote from: halosh92 on May 07, 2010, 07:08:51 pm ---36) find current first so:
first loop and 2nd loop total resistance (15*15/15+15) =7.5
so total resistance = 7.5
total Voltage = 2V
R=V/I
I=2/7.5 =0.2666666
THATS TOTAL CURRENT.......current in one loop divide by 2 = 0.133333
so IR=V
0.1333 * 5 =0.6666
and  check the choices 2/3= 0.666666
so its A

--- End quote ---

i got till the total current part, but why did u take the resistance as 5 in the next step?

Thanks alot for solving :)

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