Physics: Post your doubts here!

[Dug]

Why is the answer A:-
View attachment 22199

If the forces 3N and 4N are applied at right angles, their R = 5N. The remaining 5N can be applied in the opposite direction to R, the resultant of 3N and 4N, which will give the minimum resultant force 0.

 

[salvatore]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_22.pdf
Please help me with no. 1 (b). I do not understand how to interpret and draw the graph.
An explanation and drawing will really be appreciated.
Thanks!

 

[Light Yagami]

Why is the answer D:-

 

[Hassan Ali Abid]

spring constant = force/extention

when force is 2N ext is 90mm and when force is 0N ext is 100mm ....

change in ext is 10mm =.01m

find its gradient :-
2/-.01 = -200 N .... ignore - sign because we have to find its magnitute which is 200 N so and is D (200 N)

 

[Light Yagami]

Why is the answer C:-

 

[Hassan Ali Abid]

suppose the wavelenght of this is 2cm.....when 2 loops are produced the wavelenght decreases to 1cm .......when wavelenght decreases Frequency increases so it becomes to 2F ...
* not sure about the explaination but i think so we have to do this in this way

 

[Ahmedraza73]

Why is the answer C:-
View attachment 22234

use first harmonic and second harmonic for a fixed length of string:
lamda =2 so frequency will be f
lamda =1 frequency will be 2f

 

[Nagaanusan]

Hi everyone, AsSalamoAlaikum Wr Wb...

To get things organized in a better way, I am making this thread. As othewise, some queries remain unanswered!

So post your PHYSICS doubts in this thread. InshaAllah other people here will help me and you all.

NOTE: If any doubts in the pastpapers, please post the link! You can find links here!

Any Physics related notes and links will be added here in this post. Feel free to provide the links to your notes around the forum, or any other websites!
Thanks!
Jazak Allah Khair!

Physics Notes:

Some links & Notes - by destined007

Physics Practical Tips - by arlery

Notes for A2 Direct Sensing (Applications) - shared by sweetiepie

Physics Summarised Notes (Click to download)

AS and A-Level Physics Definitions

A2: Physics Revision notes - by smzimran

Paper:5 Finding uncerainty in log - by XPFMember

Physics Paper 5 tips - by arlery

Physics Compiled Pastpapers: <Credits to CaptainDanger for sharing this..>

Here are the compiled A level topical Physics questions in PDF form...

Paper 1 : http://www.mediafire.com/?tocg6ha6ihkwd

Paper 2 & Paper 4 : http://www.mediafire.com/?g65j51stacmy33c

(Source : http://www.alevelforum.com/viewtopic.php?f=15&t=14)

can u pls answer this question
An insect of mass 4.5mg flying with a speed of 0.12m/s-1,encounters a spider's web which brings it to rest in 2.0ms .calculate the average force exerted by the insect on the web.

this is an phy AS level question under momentum topic​

 

[Tkp]

Why is the answer C:-
View attachment 22234

the first 1 is fundamental.so the wavelength is 2l and f for the fundamental.Fr the second harmonic motion the wavelngth is l and the frequency is 2 l.

 

[Tkp]

Why is the answer D:-
View attachment 22229

f=kx(take extension in m)
so 12/(100/1000).so the ans is c.

 

[snowbrood]

can u pls answer this question​

An insect of mass 4.5mg flying with a speed of 0.12m/s-1,encounters a spider's web which brings it to rest in 2.0ms .calculate the average force exerted by the insect on the web.​

​

this is an phy AS level question under momentum topic​

favg is the average force
Favg * t = change in momentum

Favg * 2 * 10^-3 = mv - mu (v is final velocity u is initial velocity)

Favg * 2 * 10^-3 = 0 - 4.5*10^-3 * .12
now calculate for average force

 

[shinnyyy]

f=kx(take extension in m)
so 12/(100/1000).so the ans is c.

ans is C

 

[usman]

A facebook group for Further Maths, intended to remove your doubts and solve your problems. Check it out:- http://www.facebook.com/groups/furthermathsprodigies/

 

[Nagaanusan]

favg is the average force
Favg * t = change in momentum

Favg * 2 * 10^-3 = mv - mu (v is final velocity u is initial velocity)

Favg * 2 * 10^-3 = 0 - 4.5*10^-3 * .12
now calculate for average force

u r awe great

 

[Hassan Ali Abid]

ans is C

f=kx(take extension in m)
so 12/(100/1000).so the ans is c.

the answer of this is D not C

 

[1357913579]

the answer of this is D not C

f=kx
where 'x' is the change in length
k=f/x ; 12/(100-40)/1000 = 200Nm^-1

 

[Scafalon40]

Guys can someone help me with this?

If you have a raw data value like l= 6.0 +/- o.4 and you're asked to calculate l^2 and write down its absolute uncertainty, how do you know what the no of significant figures for the uncertainty should be?
And what about a number like x=750 +/- 20 and you're asked to do the same thing as above, only this time it's ln(x) which you have to calculate.
All I need to know is how many s.f should the uncertainty be quoted to.
Thanks!

 

[Muhammad TAimoor]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w05_ms_1.pdf
Mcq no. 21.
How do we solve it?!

 

[Ahmedraza73]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w05_ms_1.pdf
Mcq no. 21.
How do we solve it?!

the link that u have provide is fr marking scheme
Where is the Question Man?

 

[Tkp]

f=kx
where 'x' is the change in length
k=f/x ; 12/(100-40)/1000 = 200Nm^-1

damn.didnt see that it was 40 at first.the ans is d