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Physics MCQs thread.

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DeathDealer said:
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w09_qp_11.pdf

Ques.....13 how tention iz 60 ?

You need to use the radius and not the diameter. So divide 100 mm by 2 and you get 50mm.
Torque= Fd
F(tension)= Torque/d = 3/(50*10^-3) and you get 60 N :)
 
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DeathDealer said:
http://www.xtremepapers.me/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_w09_qp_11.pdf

Ques.....13 how tention iz 60 ?

Moment = Force x perpendicular distance

d= radius = 0.05m
Tension x perpendicular = Torque (from center of wheel)
Tx 0.05 (radius) = 3
T = 3/0.05 = 60 N
 
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kirashinagami said:
this one?
Alright this one was quite difficult and took some time. Just concentrate, Q and R are in parallel. If two equal resistors are in parallel, their equivalent resistance is half of their resistance (a fact), like 2Ω and 2Ω would give a total resistance of 1Ω (try yourself out). So suppose the resistance of each is xΩ, so the total resistance would be x + x/2 Ω = 1.5xΩ. So take the ratio 0.5x/1.5x = 1/3, that means in the parallel setup 1/3 of the power is dissipated: 1/3 of 12 = 4W. As current is halved b/w the two (Q and R), 4/2 = 2W..!!! :D
 
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RafaySid said:
kirashinagami said:
this one?
Alright this one was quite difficult and took some time. Just concentrate, Q and R are in parallel. If two equal resistors are in parallel, their equivalent resistance is half of their resistance (a fact), like 2Ω and 2Ω would give a total resistance of 1Ω (try yourself out). So suppose the resistance of each is xΩ, so the total resistance would be x + x/2 Ω = 1.5xΩ. So take the ratio 0.5x/1.5x = 1/3, that means in the parallel setup 1/3 of the power is dissipated: 1/3 of 12 = 4W. As current is halved b/w the two (Q and R), 4/2 = 2W..!!! :D

:shock: Nothing but respect for you :)
 
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cocospaniel said:
RafaySid said:
kirashinagami said:
this one?
Alright this one was quite difficult and took some time. Just concentrate, Q and R are in parallel. If two equal resistors are in parallel, their equivalent resistance is half of their resistance (a fact), like 2Ω and 2Ω would give a total resistance of 1Ω (try yourself out). So suppose the resistance of each is xΩ, so the total resistance would be x + x/2 Ω = 1.5xΩ. So take the ratio 0.5x/1.5x = 1/3, that means in the parallel setup 1/3 of the power is dissipated: 1/3 of 12 = 4W. As current is halved b/w the two (Q and R), 4/2 = 2W..!!! :D

:shock: Nothing but respect for you :)
Haha thank you thank you... :D
 
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ninjas4life said:


d= ut + 0.5at^2

since u = 0
d = 0.5at^2

1.25 = 0.5( 9.8 )t^2

t = 0.5s

d = vt for horizontal motion
10 = 0.5v
v = 20m/s
 
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diwash said:
Can any one help me with Oct/Nov 10 P12 Q no..8?

Distance travelled would be 8m. but they ask for displacement, which is a vector quantity. So 5-3= 2m. And that is the displacemet. SO the answer is A.
 
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Use the equation of motion d = ut + 0.5at^2

equation 1 : 40 = 12u + 72a

equation 2 : 80 = 18u + 162a

[I added the distances, so that initial speed of both equations will be same]

now solve these simultaneously, and you will get 0.37 m/s^2 as the answer.
 
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speed of light = 3*10^8m/s....
and 600nm=1 wavelength
or, 3*10^17nm= 3*10^17/600 = 5*10^14 and therefore C
 
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