Qualification > Sciences
A-Level Physics Paper 1 doubts (MCQ)
NidZ- Hero:
--- Quote from: Ari Ben Canaan on June 05, 2011, 09:00:04 am ---The link is broken.
--- End quote ---
thanks ari i gttta the answer
Ghost Of Highbury:
--- Quote from: NidZ- Hero on June 05, 2011, 10:53:08 am ---
A steel string on an electric guitar has the following properties.
diameter = 5.0 × 10^–4m
Young modulus = 2.0 × 10^11Pa
tension = 20 N
The string snaps, and contracts elastically.
By what percentage does a length l of a piece of the string contract?
A 5.1 × 10^–4%
B 5.1 × 10^–2%
C 1.3 × 10^–4%
D 1.3 × 10^–2 %
I know the Answers but i wanna Know hw do yu get them
Pls Show the workin
THANKS
--- End quote ---
is it B?
E = stress/ strain = FL/A*e
2.0 * 10^11 = 20l/(1.96*10^-7)e
e = 20l/12500pi
%change = e/l *100 = (20l/12500pi)/l *100 = 5.1*10^-2
NidZ- Hero:
Yeah but how
Ghost Of Highbury:
--- Quote from: NidZ- Hero on June 05, 2011, 11:14:09 am ---Yeah but how
--- End quote ---
check my previous post again (EDIT)
NidZ- Hero:
--- Quote from: Ghost Of Highbury on June 05, 2011, 11:08:07 am ---is it B?
E = stress/ strain = FL/A*e
2.0 * 10^11 = 20l/(1.96*10^-7)e
e = 20l/12500pi
%change = e/l *100 = (20l/12500pi)/l *100 = 5.1*10^-2
--- End quote ---
highbury.. how did yu get e = 20l/12500pi
where did yu get 12500pi from ???
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