Physics: Post your doubts here!

[Muskan Achhpilia]

if i am not mistaken, for number 13 ->
2F x 0.6 = 900 x 0.2
1.2 x F = 180
F = 180/1.2 = 150 N

Thank you so much!

 

[Muskan Achhpilia]

Muskan Achhpilia, I cannot see any picture from my cheap mobile, sorry. Will solve it as I get my Iphone back or tell me the year and question number, if in hurry.

Thank you anyway for your effort, and I actually don't remember the year of the paper...

 

[Thought blocker]

Thank you anyway for your effort, and I actually don't remember the year of the paper...

Are your doubts solved?

 

[Muskan Achhpilia]

Are your doubts solved?

No, not really....If you can then it would be great!

 

[Thought blocker]

No, not really....If you can then it would be great!

I said I cant see that questions. Tell me the the year. Nothing else.

 

[AnujaK]

Heeyy everyone! I've started a site that'll give you SOLVED past papers! Really helpful! Do check it out Also has some worksheets and revision notes!
https://sites.google.com/site/fromatoscom/

 

[Thought blocker]

Heeyy everyone! I've started a site that'll give you SOLVED past papers! Really helpful! Do check it out Also has some worksheets and revision notes!
https://sites.google.com/site/fromatoscom/

Amazing.

 

[Thought blocker]

Can anyone help with the following MCQs
View attachment 46182
Answer A

View attachment 46183
Answer B

View attachment 46184
Answer C

Thank you so much!

Finally I got my lappy, will solve it as I get free from my work.

 

[Thought blocker]

help me plzz

How can I?

 

[AnujaK]

Thank you!

Amazing.

 

[Thought blocker]

Can anyone help with the following MCQs
View attachment 46182
Answer A

View attachment 46183
Answer B

View attachment 46184
Answer C

Thank you so much!

Well I solved all of them and found that one of your answer is wrong. That is of kinetic energy.
So Here you go :
15)
So Clock wise moment = Anti Clock wise moment
Therefore 300 * 0.4 = 200 * 0.8
--> 40 Anticlockwise direction.
Alternative :
By taking the torque clockwise at the centre:-
=>300 x 0.4 - 200 x 0.4 = 40 Nm (clockwise)
=>Thus to balance it required torque is 40 Nm (anticlockwise)
=>(B)

13)
Already answer. Here in some more detail,
The ratio of the radius of the pulley to the arm is 0.2m/0.6m. Multiplying that by 900N gives you 300N. There are two force vectors, so 150N needs to be applied to each arm.
In other words,
To lift the weight, the cord needs to exert at least 900 N of force.
This means the disc needs to exert at least (900 N * 0.20 m) of torque.
This means the two forces on the lever needs to each exert at least (1/2 * 900 N * 0.20 m) of torque.
This means each force on the lever needs to be at least (1/2 * 900 N * 0.20 m / 0.60 m).
-> 150N

10)
This is the question where ms might not be correct or you haven't looked properly,
X = 1/2 x m x (-v)^2
Y = 1/2 x 2m x v^2 = m x v^2
Ratio of X/Y :
1/2 x m x v^2
--------------- = 1 / 2
m x v^2

Hope you got all of them.

 

[akshay 999]

why i cannot post a picture(.jpeg) when uploading has completed. If someone has a solution plz let me know

 

[Thought blocker]

why i cannot post a picture(.jpeg) when uploading has completed. If someone has a solution plz let me know

Tell me in which paper you have doubt?
Paper 1, 2, 4?
Year?
Variant?

No need to post pic if you have this info.

 

[akshay 999]

Nov 88 p1 Num 8 and the num 11




11 Water waves of wavelength 4 m are produced by two generators, S1 and S2, as shown. Each generator, when operated by itself, produces waves which have an amplitude A at P, which is 3m from S1 and 5 m from S2.






When the generators are operated in phase, what is the amplitude of oscillation at P?



A 0 B ½ A C A D 2A

 

[Thought blocker]

Nov 88 p1 Num 8 and the num 11




11 Water waves of wavelength 4 m are produced by two generators, S1 and S2, as shown. Each generator, when operated by itself, produces waves which have an amplitude A at P, which is 3m from S1 and 5 m from S2.

View attachment 46358




When the generators are operated in phase, what is the amplitude of oscillation at P?



A 0 B ½ A C A D 2A

I dont get the question.
Just fill in this :¬
Year :
Question numbers :
Session :
The detail you provide me, was like this :¬
Year : 2088 :/
Question numbers : 8 n 11
Session : Winter.
Yes? Then what is in the year 2088? how?

 

[akshay 999]

Month: November
Year :1988
paper : 1
Question number : 8

and by the way can u solve the number 11 that i have post

 

[Thought blocker]

Month: November
Year :1988
paper : 1
Question number : 8

and by the way can u solve the number 11 that i have post

I never solved 19th century paper. Please get me a link.
Bud, my iPhone is not with me nor my Mac. I have my dabba phone through which I cant see the pic you posted, its like corrupted.

 

[akshay 999]

Plz someone can help me out wiz zis questions

Question 1 : An organ pipe of effective length 0.6 m is closed at one end. Given that the speed of sound in air is 300 m/s . What is the two lowest resonant frequencies ???

Question 2 : A suspension bridge is to be built across a valley where it is known that the wind can gust at 5 second intervals. It is estimated that the speed of transverse wave along the span of the bridge would be 400 m/s. The danger of the resonant motions in the bridge at its fundamental frequency would be greatest if the span had a length of ???

Question 3 : A taut wire is clamped at two points 1.0 m apart. It is plucked near one end. Which are the three longest wavelengths present on the vibrating wire??

Question 4 : A string fixed at both ends and of length L is plucked at its midpoint and emits its fundamental note of frequency f1. When the string is plucked at a different point , the first overtone frequency f2 is also produced. Find f2/f1 and v , where v is the speed of transverse waves in the string???

 

[aliciaa]

Hi, I just obtained my AS Results for physics,I got a 72 as I didn't have time to finish quite a number of questions. Is it possible for me to still get an A for my A level? Or should I resit my AS?

 

[Thought blocker]

Plz someone can help me out wiz zis questions

Question 1 : An organ pipe of effective length 0.6 m is closed at one end. Given that the speed of sound in air is 300 m/s . What is the two lowest resonant frequencies ???

Question 2 : A suspension bridge is to be built across a valley where it is known that the wind can gust at 5 second intervals. It is estimated that the speed of transverse wave along the span of the bridge would be 400 m/s. The danger of the resonant motions in the bridge at its fundamental frequency would be greatest if the span had a length of ???

Question 3 : A taut wire is clamped at two points 1.0 m apart. It is plucked near one end. Which are the three longest wavelengths present on the vibrating wire??

Question 4 : A string fixed at both ends and of length L is plucked at its midpoint and emits its fundamental note of frequency f1. When the string is plucked at a different point , the first overtone frequency f2 is also produced. Find f2/f1 and v , where v is the speed of transverse waves in the string???

What problem you are facing in this? Look I am online from my dabba phone as I said, so will reply slower.
2)
5s intervals is a frequency f = 1/T = 1/5 = 0.2Hz.

Since v = fλ, the wavelength for transverse wave on the bridge is given by
400 = 0.2λ
λ = 2000m

At the fundametal frequency, the bridge's length iequals λ/2 (node to node), so the danger is greatest at 2000/2 = 1000m

4)
Rememeber the distance between 2 nodes is λ/2. See link (http://www.solitaryroad.com/c1031/ole.gif)

The fundamental (f₁) is sometimes called the 1st harmonic.
If the string is length L, then L= λ₁/2. So λ₁ = 2L.

The first overtone (f₂) is is sometimes called the 2nd harmonic.
If the string is length L, then L= 2(λ₂/2) = λ₂
_________________________________

v = λ₁f₁ = (2L)f₁ = 2Lf₁

v = λ₂f₂ = Lf₂

Therfore
2Lf₁ = Lf₂
f₂/f₁ = 2