physics

[Phosu]

how do we find the resistances?

[Phosu]

D IN THE ANSWER



THEN  R x 16

rong ans is A

[Phosu]

A mass of a liquid of density ? is thoroughly mixed with an equal mass of another liquid of density
2?. No change of the total volume occurs.
What is the density of the liquid mixture?
A)4/3? B)3/2? C)5/3? D)3?

[halosh92]

how do we find the resistances?

see
the voltage at R3 is 2V
at R2 its 1V
at R1 its 2V   (because all add up to 5V)
therefore R3 and R1 have same voltage therefore same resistance so its C

[halosh92]

The filament of a 240 V, 100W electric lamp heats up from room temperature to its operating temperature. As it heats up, its resistance increases by a factor of 16.

What is the resistance of this lamp at room temperature?
A)36? B)580? C)1.5k? D)9.2k?

P=IV
100/240= I (its in decimals so i wont write it)
R=V/I
R=240/I  =576
576/16= 36

[halosh92]

A mass of a liquid of density ? is thoroughly mixed with an equal mass of another liquid of density
2?. No change of the total volume occurs.
What is the density of the liquid mixture?
A)4/3? B)3/2? C)5/3? D)3?

whats the "?" in ure doubt..retype ure question plz

[Phosu]

ah the ? is the symbol for density...
A mass of a liquid of density "p" is thoroughly mixed with an equal mass of another liquid of density
2?. No change of the total volume occurs.
What is the density of the liquid mixture?
A)4/3p B)3/2p C)5/3p D)3p

[Phosu]

see
the voltage at R3 is 2V
at R2 its 1V
at R1 its 2V   (because all add up to 5V)
therefore R3 and R1 have same voltage therefore same resistance so its C

how did u find these voltages?

[halosh92]

how did u find these voltages?

look at the diagram and treat each resistor as if its alone like first resistor its between the 0V and 2V
and second resistor its between 2V and 3V ...basically 3-2=1V
and the 3rd ...we know that total voltage is 5V its between 3V and 5V therefore 5-3=2V
got it?

[33oomar]

i got a proplem in IGCSE physics paper 6 May/june 08 Q4 C

[Saladin]

i got a proplem in IGCSE physics paper 6 May/june 08 Q4 C

What do you not understand about this?

[33oomar]

all of it
please help me

[Phosu]

got it Thanks!

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

[33oomar]

one more thing 
i was wondering can i plot a broken x axis on a graph or not

[halosh92]

got it Thanks!

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

q9)  s=ut+ 1/2at^2
s=1/2at^2
2h=at^2
2h= a (t2 ^2 - t1^2)
2h/(t2 ^2 - t1^2) =a

11) speed of approach=speed of separation
uA - uB = vA - vB
different directions lets take this direction -----------> as (+)
so
uA-(-uB)=vA + vB


12) ------------> take as (+)
 m1u1 + m2u2= m1v1 +m2v2
m1 *60 + (m2 * -30) = m1v +m2v       (v is same)
cancel out the "m"
60-30 = 2v
30/2=15