- #1
Junkwisch
- 31
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Homework Statement
"the question is included in the attachment"
Homework Equations
F=ks, E=stress/strain=(force/area)/(change in L/L)
Second moment of inertia=I=(1/2)*base*height^3
The Attempt at a Solution
Sice F=ks
k=F/s where F=p and s= d(L) (change in L)
E=(P/A)/(strain)=> EA(Strain)=P E=Young Modulus A = Area
area of the beam is equal to base*height, let height be equal to L
Second moment of inertia=I=(1/2)*base*height^3 => base=b= (12*I)/(L^3)
Thus P=E*(strain)*L*b=(E*dL*12*I)/(L^3)
Thereby K=P/s=P/dL=(12*I*E)/(L^3)
However the suppose answer is (48*I*E)/(L^3), can anyone tell me what I did wrong?