Physics: Post your doubts here!

[A.ELWY 7]

View attachment 11456
how do you find Q 2 part b???

can u pls say what year is this..i got an answer and need to check if it is rightor wrong

 

[Peter Check]

um first of all it was question 1 a ii....ok and yes the answer is 2.08 because as u answered in the first part a change would be +or- 0.0205...so maximum vlaue must be 2.05 + 0.0205=2.0705..then he said in the question that there is +or - 1digit..so 1 digit means 0.01 so 2.0705+0.01=2.0805..wish u understood.

why do we assume plus minus 1 digit means 0.01, for example why cant it be 3.05?

 

[Peter Check]

What is the difference between cells arranged in parallel and in series!!, In series I know just to add them up and get the final emf, but how parallel work?

 

[A.ELWY 7]

why do we assume plus minus 1 digit means 0.01, for example why cant it be 3.05?

because he gave you the voltage which is 2.05..so when he says 1 digit, it means to start count from the end which is in this case the 5..so its is 0.01...maybe im wrong but this is the way i was teached and it worked!!

 

[Wanzi21]

can u pls say what year is this..i got an answer and need to check if it is rightor wrong

June 11 paper 21

 

[A.ELWY 7]

What is the difference between cells arranged in parallel and in series!!, In series I know just to add them up and get the final emf, but how parallel work?

in series: Vtotal=V1+V2+V3 .... Itotal=I1=I2=I3 .... Rtotal=R1+R2+R3..
In parallel: Vtotal=V1=V2=V3 .... Itotal=I1++I2+I3.... Rtotal= 1/R1+ 1/R2 + 1/R3 ...

 

[Tasnuva]

Guys I'm from Bangladesh and my physics paper 22 exam got postponed by 8 hours tomorrow. It was supposed to be held at 11.00 in the morning and now it got postponed to 7.30 in the evening. Whoever will be done, please post anything that you remember from the paper. Thanks!

 

[A.ELWY 7]

June 11 paper 21

ok the question asked for the component of the weight DOWN THE SLOPE...so resolving the forces gives us the W component as mg sin (theta) so m=850kg, 850 x 9.81 sin (7.5)= 1088 so about 1090N

 

[lavanyamane]

well its easy . look, continue the line of sphere B till the time (t) where the graph of A starts to descend. ! then ,contiune the graph by ascending the line wid constanst positive gradient , now the tricky part is , that till where the gradient must b kept constant, for this, u have to consider the change in velocity of sphere A , like, it changed from 6 to -3 which makes it 6+3=9 (change in momentum) , same way , sphere B starts wid Momentum -4,
so by keeping constant the change in momentum, we can calculate the final momentum of sphere B ,
X-(-4)=9 , answer will b 5 , so the graph will ascend till the momentum is 5 , after which it will continue as a straight line wid zero gradient , hope u got it

Yes, I did! Thank you so much! Also, what is eVand MeV? I'm afraid I haven't ever come across these. http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_23.pdf Q.7(b)(i)

 

[A.ELWY 7]

Winzi 21...just if you didnt know this before...for any object on an inclined plae the component down the slope is mg sin (theta) and vertically downwards perpendicular to the component down hte slope is mg cos (theta)

 

[Most_UniQue]

Oh yes, the electric field. How stupid of me x_x Thank you! Could you help me with this one?
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_22.pdf Q.3(c)

 

[leosco1995]

Yes, I did! Thank you so much! Also, what is eVand MeV? I'm afraid I haven't ever come across these. http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_23.pdf Q.7(b)(i)

eV = electron volt, and MeV = mega electron volt.

e = magnitude of charge on electron = 1.6 x 10^-19. Units = C.
V = voltage. Units = J/C.

When they multiply, the units of C cancel out so you are left with J, meanings its a energy quantity. The M just means mega (10^6).

So if you want to calculate for example, the value of 1.4 MeV, then it would be:

1.4 * 10^6 * 1.6 * 10^-19 J.

 

[Hassi123]

The qb proves that time is same and change in momentum is same aswell. there is a change in momentum of sphere A from 6 to -3 (total change of 9) , hence sphere B will increase by the same, so from -4 to +5 (-4+9=5)

 

[Hassi123]

eV = electron volt, and MeV = mega electron volt.

e = magnitude of charge on electron = 1.6 x 10^-19. Units = C.
V = voltage. Units = J/C.

When they multiply, the units of C cancel out so you are left with J, meanings its a energy quantity. The M just means mega (10^6).

So if you want to calculate for example, the value of 1.4 MeV, then it would be:

10^6 * 1.6 * 10^-19 J.

and wont you multiply that value by 1.4 after that? :O

 

[geek101]

ms: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_ms_22.pdf
qp: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_22.pdf

in question 2bii, if you rearrange the equation you get that r and v are inversely proportional...so in the question if the radius is decreased the velocity is supposed to be more. someone please explain what the mark scheme says for this

 

[Peter Check]

in series: Vtotal=V1+V2+V3 .... Itotal=I1=I2=I3 .... Rtotal=R1+R2+R3..
In parallel: Vtotal=V1=V2=V3 .... Itotal=I1++I2+I3.... Rtotal= 1/R1+ 1/R2 + 1/R3 ...

For V total in parallel, what if one emf is 3V and the other is 10V?? Then how can Vtotal=3=10 ??

 

[gary221]

How do v do this???

Ans is 2...May/June 2009

 

[Shomail Arif]

Can someone please post a link to all the important formulass? Thankss

 

[geek101]

ms: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_ms_22.pdf
qp: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_22.pdf

in question 2bii, if you rearrange the equation you get that r and v are inversely proportional...so in the question if the radius is decreased the velocity is supposed to be more. someone please explain what the mark scheme says for this

 

[Goku]

Can someone please post a link to all the important formulass? Thankss

Here you go!