Biology; Chemistry; Physics: Post your doubts here!

[iamLbert]

How long is Physics Paper 1 for EXPO Candidates? Mine centre is 1 h

 

[AhsanAfzal]

Your center must be Expo center.

yes

 

[AhsanAfzal]

This is very unfair thing. Many of my friends got this centre and every time almost every time light goes out and extra 30 minutes!!

last time we got 10 minute in chemistry atp

 

[AhsanAfzal]

why is the answer A ?

 

[Snowysangel]

View attachment 27344
why is the answer A ?

Cause the resultant force, called the centripetal fotce) always acts toward the Center of acurved path...IT ONLY APPLIES TO CIRCULAR PATHS though

 

[usama321]

Cause the resultant force, called the centripetal fotce) always acts toward the Center of acurved path...IT ONLY APPLIES TO CIRCULAR PATHS though

the question is about friction?

 

[Mohammad Farzanullah]

i was about to ask the same question!

 

[Mohammad Farzanullah]

i think that it should be C bcoz it is asking about the frictional force! but it is A in marking scheme!

 

[Snowysangel]

Yeah so the frictional force acts toward the Center of the turntable. The couns moving because of the frictional force...so to speak, it becomes the coins force. To keep the coin at the same distance from the Center if the turntable, there has to be a force on rhe coin acting toward it...to resist the coins inertia (orherwise it'll go straight in the direction of b)

 

[Mohammad Farzanullah]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s10_qp_12.pdf

hey can anyone plz expain Q26. i cant understand the question even!
your help would be highly rewarded!

 

[iamLbert]

Friends, can u help me in Q3 of Physics OL 2009 Paper 2 ? Thanks.

 

[mannat0033]

how do you resolve vectors? and the application if cos and sin ?

 

[Amnaa]

http://papers.xtremepapers.com/CIE/Cambridge%20International%20O%20Level/Physics%20(5054)/5054_s03_qp_1.pdf
question no.1 -_-

 

[asma tareen]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s03_qp_1.pdf
question no.1 -_-

its B i guess

 

[Amnaa]

its B i guess

yes.. it is.. but how?

 

[asma tareen]

yes.. it is.. but how?

firstly look at the main scale it shows 6.5 then look at the second scale and observe whic point is alligned with the main scale it 0.05 add both values u'll get 6.55

 

[Saad Mughal]

yes.. it is.. but how?

Main scale Reading = 6.5 cm
Secondary scale reading = 0.05 cm
Vernier scale reading = 6.55 cm

 

[Saad Mughal]

the question is about friction?

The key words are "keeps the coin moving". This tells us that the frictional force is the resultant force on the coin (it is the centripetal force since the coin is in circular motion).

 

[Saad Mughal]

Friends, can u help me in Q3 of Physics OL 2009 Paper 2 ? Thanks.

(a) The power is given in Watts so convert the time to Seconds.
Time = 2 * 60 = 120 s.
Power = Energy/Time,
Energy = Power * Time
Energy = 85 * 120
Energy = 10200 J

(b) Specific Latent Heat = Energy Supplied/Mass
Specific Latent Heat = 10200/31
Specific Latent Heat = 329.0 J/g (3 sig. fig.)

(c) This is because the energy required to heat the ice to 0 deg. C is also to be taken into account and hence, the energy supplied for 'melting' the ice would be less in the first 2 minutes.

 

[iamLbert]

(a) The power is given in Watts so convert the time to Seconds.
Time = 2 * 60 = 120 s.
Power = Energy/Time,
Energy = Power * Time
Energy = 85 * 120
Energy = 10200 J

(b) Specific Latent Heat = Energy Supplied/Mass
Specific Latent Heat = 10200/31
Specific Latent Heat = 329.0 J/g (3 sig. fig.)

(c) This is because the energy required to heat the ice to 0 deg. C is also to be taken into account and hence, the energy supplied for 'melting' the ice would be less in the first 2 minutes.

thanks pal ar u taking ol physics? if u ar, good luck then