Physics: Post your doubts here!

[VelaneDeBeaute]

part (a) (i) change in gravitational potential energy.

The gravitational potential energy has the formula GMm/x where x is the distance. We have to calculate the change in GPE so we will find the difference for each of the quantities in the formula. G M and m are constant, and hence the only thing that varies is the x. Now x is equal to the difference in the two distances. One being the (R + h1) and other being the (R + h2). h1 and h2 are distances from the surface of earth, whereby we need the distances from the centre of the earth.
Hence the final formula would become {GMm/(R+h1)} - {GMm/(R+h2)}. You could simplify this to get to the answer in the marking scheme.

 

[D0cEngi]

The gravitational potential energy has the formula GMm/x where x is the distance. We have to calculate the change in GPE so we will find the difference for each of the quantities in the formula. G M and m are constant, and hence the only thing that varies is the x. Now x is equal to the difference in the two distances. One being the (R + h1) and other being the (R + h2). h1 and h2 are distances from the surface of earth, whereby we need the distances from the centre of the earth.
Hence the final formula would become {GMm/(R+h1)} - {GMm/(R+h2)}. You could simplify this to get to the answer in the marking scheme.

thank u so much..

 

[D0cEngi]

The gravitational potential energy has the formula GMm/x where x is the distance. We have to calculate the change in GPE so we will find the difference for each of the quantities in the formula. G M and m are constant, and hence the only thing that varies is the x. Now x is equal to the difference in the two distances. One being the (R + h1) and other being the (R + h2). h1 and h2 are distances from the surface of earth, whereby we need the distances from the centre of the earth.
Hence the final formula would become {GMm/(R+h1)} - {GMm/(R+h2)}. You could simplify this to get to the answer in the marking scheme.

Plz help me with this ques also: Q.5 part (b) of this paper: http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf
here is the ms : http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_ms_4.pdf

 

[VelaneDeBeaute]

Plz help me with this ques also: Q.5 part (b) of this paper: http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf
here is the ms : http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_ms_4.pdf

Well! For this, you just remember that connecting capacitors in series decreases their effective capacitance while being in parallel increases it.(It is almost the same as you used to do with resistors in AS). Anyway, so two resistors in series connected with a similar arrangement in parallel will provide you with an effective capacitance of 4500 uF. (Try calculating the capacitance of the whole arrangement and you'll get the answer 4500 uF which signifies it is correct! )

 

[A*(a*)]

Here the person who can help all of us. He posted the answers to A2 chapters, He would definitely have the AS ones too!
http://www.xtremepapers.com/community/threads/physics-coursebook.14175/

 

[SilverCrest]

Two bodies of equal mass are moving towards each other ,one with a speed of 40cm/s and the other with a speed of 60cm/s>they stick together on impact.What is the velocity after impact?

Can someone please explain how i am to go about this question?the answer is 10cm/s by the way ..but i dont understand this question

 

[Taci12]

Two bodies of equal mass are moving towards each other ,one with a speed of 40cm/s and the other with a speed of 60cm/s>they stick together on impact.What is the velocity after impact?

Can someone please explain how i am to go about this question?the answer is 10cm/s by the way ..but i dont understand this question

Momentum is always conserved, hence:

total initial momentum = total final momentum

Before impact : Since they are moving towards each other, the velocity of one is negative with respect to the other.

After impact: As they stick together after impact, they move along with the same velocity. Together, they have mass 2m.

60m + (-40m) = 2m x v
v= 10 cms

 

[workaholic]

Can anyone please tell me in detail how to change the frequency of the current in Q1 of the following p5 paper....I gotta paper tomorrow so plz help quickly....The mark scheme is quite vague......
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w10_qp_51.pdf

yaar guyz plz answer my question also.....

 

[D0cEngi]

Well! For this, you just remember that connecting capacitors in series decreases their effective capacitance while being in parallel increases it.(It is almost the same as you used to do with resistors in AS). Anyway, so two resistors in series connected with a similar arrangement in parallel will provide you with an effective capacitance of 4500 uF. (Try calculating the capacitance of the whole arrangement and you'll get the answer 4500 uF which signifies it is correct! )

Thank u once again..

 

[D0cEngi]

tell me how to prepare for paper 5 in just one day..?

 

[D0cEngi]

Plz help me in Q.2 part (e) of this paper: http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_5.pdf

 

[Taci12]

yaar guyz plz answer my question also.....

All you have to do is use an A.C signal generator connected to the coil. The frequency of the current can then be simply changed by varying the settings on the signal generator. All the best for your paper!

 

[Taci12]

tell me how to prepare for paper 5 in just one day..?

Some tips for P5 : http://www.xtremepapers.com/community/threads/physics-p5-some-tips-for-question-1.21570/

All the best

 

[D0cEngi]

Some tips for P5 : http://www.xtremepapers.com/community/threads/physics-p5-some-tips-for-question-1.21570/

All the best

Thank u..

 

[kronix6]

HI all. Can anyone solve this question for me and explain its concept and working plz. ill be grateful

Question number 4 . part( b ). sub-part (ii).
Paper 4
May/June 2008
Physics

Thanks in advance

 

[Ding Ding]

what is not conserved in nuclear processes?

A energy and mass together
B nucleon number
C neutron number
D charge
Why the answer is neutron number? Is the charge is conserved?
someone can help me ??

 

[Taci12]

what is not conserved in nuclear processes?

A energy and mass together
B nucleon number
C neutron number
D charge
Why the answer is neutron number? Is the charge is conserved?
someone can help me ??

Neutron number is not conserved as neutrons can decay to form a proton and an electron. Both the initial net charge and final net charge in this nuclear reaction is zero, charge is always conserved.

 

[Taci12]

HI all. Can anyone solve this question for me and explain its concept and working plz. ill be grateful

Question number 4 . part( b ). sub-part (ii).
Paper 4
May/June 2008
Physics

Thanks in advance

Net potential = potential due to A + potential due to B

electric potential = Q/ 4πε0r , here r is given by x

using the first formula:

0= (3.6 × 10–9) / (4πε0 × 18 × 10–2) + q / (4πε0 × 12 × 10–2)
q= –2.4 × 10–9 C

 

[SilverCrest]

Peace be upon you!
Can somebody explain mcq number 10 ,17 and 14 of:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s12_qp_13.pdf

And also mcq 17 of:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_13.pdf
Thank You!

 

[iFuz]

I need Notes for Gravitation, Circular Motion, Geostationary satellites and Momentum!