Physics: Post your doubts here!

[DeViL gURl B)]

http://maxpapers.com/syllabus-mater...hment/9702_may-june-2011-all-question-papers/

physics, May June 2011 paper 41 question 4 part (i) (ii) along with (c) .. can someone please EXPLAIN THIS QUESTION. ITS REALLY CONFUSING.
and in part (c) they've used the elementary charge but taken "-19" as "19" only .. in fact , all the negative values are taken as positive .. i don't get why.
CAN SOMEONE PLEASE HELP.
THANK YOU.

PLEASE URGENT HELP.

 

[immie.rose]

Please help me with Q6 (b)(ii) and (iii). Why is there a phase difference of 90 for emf induced in secondary coil?
http://freeexampapers.com/A-Level/Physics/CIE/2005-Jun/9702_s05_qp_4.pdf
http://freeexampapers.com/A-Level/Physics/CIE/2005-Jun/9702_s05_ms_4.pdf

 

[princess Anu]

whats wrong if I do it like this? because the answer or the phase diff between these two points is actually 270. And I do understand how, but I don't understand whats wrong in this method?

 

[Xylferion]

View attachment 51739 whats wrong if I do it like this? because the answer or the phase diff between these two points is actually 270. And I do understand how, but I don't understand whats wrong in this method?

Each wave cycle is 360 degrees. You cannot just put the degrees where you want, you have to make sure each wave lasts a complete 360 degrees. Like so...



Hope that made sense

 

[DeViL gURl B)]

PLEASE URGENT HELP.

http://maxpapers.com/syllabus-mater...hment/9702_may-june-2011-all-question-papers/

physics, May June 2011 paper 41 question 4 part (i) (ii) along with (c) .. can someone please EXPLAIN THIS QUESTION. ITS REALLY CONFUSING.
and in part (c) they've used the elementary charge but taken "-19" as "19" only .. in fact , all the negative values are taken as positive .. i don't get why.
CAN SOMEONE PLEASE HELP.
THANK YOU.

anyone?

 

[Physux]

\

Alright.. so for question 2, you need to find the torque. Torque is force x perpendicular distance between two forces. In that diagram you're already given the distance which is 0.30 m. However, the forces are not perpendicular, So you're going to want to find the vertical components. That is 2 Sin 50.

Now put that stuff into the formula, 2 Sin 50 x 0.30 m = 0.459 Nm. Which rounds up to 0.46 Nm.

---------------
I already explained question 6 above, have a read through it.
---------------
For question 9,

View attachment 51735

Look at the diagram above, what I did was add the tails of each force, to the heads of the other.
You end up with a rhombus. Now the original two forces, the 10 N ones acting 120 degrees apart, act " outwards ". The resultant force will act outwards as well. Hence why I labelled that line running through the middle, R.

Now further inspection of R, should show you that it bisects 120* in half. This leaves 60 degrees on either side. Now that you have two equal angles and two equal sides, this should become more obvious to you :-
View attachment 51736
With this in mind, the final side will be of magnitude 10N and its counter-part angle will be 60 degrees.

NOTE:- You can tell it bisects in half if you touch up on the laws of a rhombus.

This isn't the only way to approach this question, but it's in my opinion, the easier approach. You could attempt to use a variation of the cosine rule, in which there is a slight difference in the sign usage.

Hope that helped. ^_^

Thanks a lot. I got them all. For the last question why can't I use the sine rule to find the unknown vector? I mean I tried that but I'm not getting the right answer.

 

[Xylferion]

\

Thanks a lot. I got them all. For the last question why can't I use the sine rule to find the unknown vector? I mean I tried that but I'm not getting the right answer.

It all depends on which direction you consider the resultant force to act.


However, this will

If you find that you can manage calculations in a multiple choice exam, be my guest and use this method ^_^

 

[mariamfaizal41097]

s02 q3bi

 

[ashcull14]

HELP PLEASE !

 

[immie.rose]

please help Q6(ii) http://freeexampapers.com/A-Level/Physics/CIE/2005-Nov/9702_w05_qp_4.pdf
http://freeexampapers.com/A-Level/Physics/CIE/2005-Nov/9702_w05_ms_4.pdf

 

[Xylferion]

View attachment 51817
HELP PLEASE !

Ok so.... firstly, you need to look at the directions the forces are acting. BOTH forces are acting inwards onto the particle, as a result of this, the resultant force will also act inwards.

The next step is figuring out the direction in which it acts, you can find this out by attaching the tail of one force to the head of the other.

Then you use your knowledge of vector addition and you would end up with something like this...

and then you move towards something like this,


Now for the second part, to prove that the resultant force is 6.6 N. You use the diagram in which you applied the nose to tail method.

From this you can use the cosine rule, since you have a) two known sides and b) one unknown side with a known angle

R^2 = (2.5)^2 + (7.5)^2 - ( 2 x 7.5 x 2.5 x Cos 60 )
R^2 = 62.5 - 18.75
R^2 = 43.75
R= 6.6143 N

Which rounds up to 6.6 N, since both 2.5N and 7.5N are given to 2 significant figures.

Hope that helped!

 

[Bba321]

Hey how do we conver signal voltages to binary numbers?

 

[Bba321]

Also how d we know f it's above or below reference level in 14 part b
Thanks
june /04/6 Qs 14

 

[The Sarcastic Retard]

I want to learn basic concepts of graph. Like when accn is constant, there is uniform velocity, area under graph of vt gives disp, slope of vt gives accn etc etc...
I have exams tommorow. HELP ASAP.

 

[ashcull14]

Ok so.... firstly, you need to look at the directions the forces are acting. BOTH forces are acting inwards onto the particle, as a result of this, the resultant force will also act inwards.

The next step is figuring out the direction in which it acts, you can find this out by attaching the tail of one force to the head of the other.
View attachment 51828
Then you use your knowledge of vector addition and you would end up with something like this...
View attachment 51829
and then you move towards something like this,
View attachment 51830

Now for the second part, to prove that the resultant force is 6.6 N. You use the diagram in which you applied the nose to tail method.
View attachment 51831
From this you can use the cosine rule, since you have a) two known sides and b) one unknown side with a known angle

R^2 = (2.5)^2 + (7.5)^2 - ( 2 x 7.5 x 2.5 x Cos 60 )
R^2 = 62.5 - 18.75
R^2 = 43.75
R= 6.6143 N

Which rounds up to 6.6 N, since both 2.5N and 7.5N are given to 2 significant figures.

Hope that helped!

very well xplained thnk u so much

 

[DeViL gURl B)]

may june 2007 paper 4 question 3
PLEASE SOMEONE HELP. DETAIL OF HOW TO FIND THE AREA

 

[Straw-Hat]

9702 physics MJ 04
Question no. 9 b
I didn't understand the question? Can any one please explain the questtion and how should I solve it?

 

[smhfifa]

Can anyone tell me why is the papers webpage not working, it is saying that the webpage is not available, this is the site papers.xtremepapers.com

 

[immie.rose]

may june 2007 paper 4 question 3
PLEASE SOMEONE HELP. DETAIL OF HOW TO FIND THE AREA

hope this helps!

 

[DeViL gURl B)]

hope this helps!

thank you soo much.
so basically the formula used is of the area .. right?