Physics: Post your doubts here!

[Mikaila]

W'12 P13
Q 25.) A lift is supported by two cables, each of length 10m and diameter o.5cm. The lift drops 1mm when a man of mass 80kg steps into the lift. What is the best estimate of the value of the Young Modulus of steel?
The answer is C which is 2x10^11...
Please can u explain how to arrive at the answer.

 

[salvatore]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w07_qp_2.pdf
Please help me solve qn no. 3 (b). It seems easy but I just can't think of the solution..
Thanks

 

[Tkp]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w07_qp_2.pdf
Please help me solve qn no. 3 (b). It seems easy but I just can't think of the solution..
Thanks

at first the initial height was 61.then when the pendulum swings the vertical height would be 61cos 18.so u need to to find the gain in potential energy.mg(h2-h2)

 

[salvatore]

at first the initial height was 61.then when the pendulum swings the vertical height would be 61cos 18.so u need to to find the gain in potential energy.mg(h2-h2)

Thank you for your reply..
This is where I'm stuck.. how did you get 61cos18??

 

[Tkp]

Thank you for your reply..
This is where I'm stuck.. how did you get 61cos18??

cos18=h/61.ok just see at first when the pendulum didnot swing the initail height was 18.but when it started swinging it gain an height and u need to find the difference in height.hope i made u clear

 

[Tkp]

W'12 P13
Q 25.) A lift is supported by two cables, each of length 10m and diameter o.5cm. The lift drops 1mm when a man of mass 80kg steps into the lift. What is the best estimate of the value of the Young Modulus of steel?
The answer is C which is 2x10^11...
Please can u explain how to arrive at the answer.

same problem here

 

[1357913579]

W'12 P13
Q 25.) A lift is supported by two cables, each of length 10m and diameter o.5cm. The lift drops 1mm when a man of mass 80kg steps into the lift. What is the best estimate of the value of the Young Modulus of steel?
The answer is C which is 2x10^11...
Please can u explain how to arrive at the answer.

see first off all when the lift moves 1mm down each of the steel cable expand with an extention of 1mm.
-the downward force by man is (80)(9.81)=784.8N
-this is the sum of the force applied to those 2 steel cables
- as both have the same dimention they will experience the same force
- 2f=784.8 where f is the force experienced by one steel cable
-f=392.4
-young modulus=fl/eA
-A=pi(0.25x10^-2)2=1.96x10^-5 m
-lenth is given
-extension is given convert it to metre
-plugin in the point youll get the answer.

 

[snowbrood]

same problem here

 

[snowbrood]

hehe theres already an answer for that so

 

[Arjun Dhanak]

Hey.. has anyone made a chapter wise set of papers for A level physics? If so then pls reply with the link.
Thanks in advance.

 

[Soldier313]

Hey.. has anyone made a chapter wise set of papers for A level physics? If so then pls reply with the link.
Thanks in advance.

there you go

https://www.xtremepapers.com/community/threads/physics-p1-p2-p4-past-papers-chapter-wise-d.13931/

 

[daredevil]

hii can anyone oks give me good notes on young modulus?? I misseed that topic and can't seem to grasp it now :/
pls hellp if u can

 

[sma786]

Ok, so this year i'm giving my AS level in may june, but no matter how hard i read the books and notes,etc. I always get confused by the past papers! Never has it happened that oh wow i did almost the entire past paper perfectly, in every paper i find a new type of question ! help please?

 

[Jspake]

Please help me solve the question above.. a good explanation will be appreciated.
Thanks!

 

[Tkp]

Please help me solve the question above.. a good explanation will be appreciated.
Thanks!

u need to find the squares that how much it lags behind t1
so phase difference is 60.so apply the formulae 60/360=t/30.then u will get the number of squares it is lagging and the amplitude is same

 

[Jspake]

u need to find the squares that how much it lags behind t1
so phase difference is 60.so apply the formulae 60/360=t/30.then u will get the number of squares it is lagging and the amplitude is same

Thank you for your help.
I still don't get the solution.. in the formula 60/360 = t/30, where did you get the 30 from? Please elaborate..

Sorry for bothering you.. waiting for your reply!

 

[Ahmedraza73]

Thank you for your help.
I still don't get the solution.. in the formula 60/360 = t/30, where did you get the 30 from? Please elaborate..

Sorry for bothering you.. waiting for your reply!

Phi=t/T*360
Phi is a greek letter for phase differnce in angles or radians

 

[Tkp]

Thank you for your help.
I still don't get the solution.. in the formula 60/360 = t/30, where did you get the 30 from? Please elaborate..

Sorry for bothering you.. waiting for your reply!

the number of squares to complete a wavelength

 

[Ahmedraza73]

A stationary thoron nucleus (A=200,Z=90)emits an alpha particle with kinetic energy Ealpha(Ea).which is the Kinetic Energy of the recoiling nucleus?
A: Ea/108
B: Ea/110
C: Ea/54
D: Ea/55
E: Ea
Please can anyone solve this?

 

[Light Yagami]

Why is the answer A:-