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Can someone please explain the rules of applying different formulas for calculating % uncertainty? e.g. OCT 2003 Q4.
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Physics MCQs thread.
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arlery said:
power = Force * velocity.
Crane's weight = 1000
mass weight = 10000
velocity of both = .5
power by crane = 1000 * 0.5 joules =550 W
power by mass = 10000 * .5 = 5000 W
total power = 5500 W = 5.5 kW
Let's suppose the current is I. Using parallel/series, P gets I, and Q and are both get I/2. Power across P will therefore be given as I^2*R, and that across Q will be (I/2)^2*R. Same for R. This will simplify to I^2/4*R.mickysharif said:
So we can see the ratio for the powers across P:Q:R are 4:1:1.
Using ratio theorem, power across R can be found.
1/6 * 12 = 2.
can someone tell how the answer to Q.9 is B in this paper:
http://www.xtremepapers.me/CIE/Internat ... 7_qp_1.pdf
http://www.xtremepapers.me/CIE/Internat ... 7_qp_1.pdf
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Thankyou both. very well explained, and best of luck for the exam.
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ivorydale said:
max height (displacement) by object is when v= 0
so thats when t=3
when t=3 , displacement = area under graph = 45
then ball starts falling down in opposite direction... Displacement will be negative
so for next two seconds, at t = 5, area under graph = 2O
displacement for next 2 seconds is -20
total displacement = displacement for 5 seconds = 45 + (-20) = 25 m
B answer
Draw a rough sketch of the path the ball might have travelled. V=0 at the highest point, so label t=3 at the peak of your sketch. t=5 comes b/w t=3 and ground level. So you will realize that to get displacement from the ground, u need to subtract area b/w t=3 to t=5 from t=0 to t=3.ivorydale said:
http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf
PLZ HELP ME WITH QUESTION 34 of this paper!!!! URGENTLY!!!!!
PLZ HELP ME WITH QUESTION 34 of this paper!!!! URGENTLY!!!!!
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bloooooo said:
each wire has 0.005 ohm per meter resistance.
Resistance for 800 m for each wire = 800 * .005 = 4 ohm
Two wires (they are in series)
total R = 8 ohm
V for wires = IR = 8* .6 = 4.8
total V = 16+4.8= 20.8
so minimum V is C ..
The most common issue with that is ppl forget that there are two wires, so instead of 800m, 1600m should be taken as the length. This will give 0.005*1600 =8 as total resistance of wire.bloooooo said:
V=IR will give V=(0.6)(8) =4.8v, which are used in overcoming resistance of the wire.
Add this to 16, and you get the answer, 20.8
http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf here is the link , Please help with question 23 and 28 guys 
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gexceln said:
they have equal resistances...
The second one is cut into smaller wires of equal length
but when u put all those together, it just forms the first one single wire, as both have same volume..
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pspwxpfan said:
its C