Civil Engineering - Strength of Materials - Discussion
Discussion Forum : Strength of Materials - Section 1 (Q.No. 33)
33.
For a simply supported beam of length L, the bending moment M is described as M = a (x - x3/L2), 0 ≤ x < L; where a is a constant. The shear force will be zero at
Discussion:
8 comments Page 1 of 1.
Abdullah said:
1 year ago
dM/dx = a( 1 - 3x^2/L^2).
Now to get max shear force, dM/dx = 0.
So, a( 1 - 3x^2/L^2) = 0.
L^2 = 3x^2.
x^2 = (L^2)/3
x = L/√3.
Now to get max shear force, dM/dx = 0.
So, a( 1 - 3x^2/L^2) = 0.
L^2 = 3x^2.
x^2 = (L^2)/3
x = L/√3.
Shreyas A said:
5 years ago
We know that,
Rate of change of Bending moment, dM/dx = Shear force.
Rate of change of Shear force, dF/dx = Rate of loading.
So, they gave B.moment as an equation. To get Shear force then differentiate that wrt x and we will get,
dM/dx = a( 1 - 3x^2/l^2).
Now to get max shear force, dM/dx = 0.
so, a( 1 - 3x^2/l^2) = 0.
l^2 = 3x^2.
x = l/√2.
Rate of change of Bending moment, dM/dx = Shear force.
Rate of change of Shear force, dF/dx = Rate of loading.
So, they gave B.moment as an equation. To get Shear force then differentiate that wrt x and we will get,
dM/dx = a( 1 - 3x^2/l^2).
Now to get max shear force, dM/dx = 0.
so, a( 1 - 3x^2/l^2) = 0.
l^2 = 3x^2.
x = l/√2.
(1)
ANJALI said:
5 years ago
Shear force always zero at maximum bending moment.
For max BM,dm/dx =0.
So 1-3x^2/l^2 =0.
Hence, 1-3x^2=0.
x=1/3^1/2.
For max BM,dm/dx =0.
So 1-3x^2/l^2 =0.
Hence, 1-3x^2=0.
x=1/3^1/2.
Hussein said:
6 years ago
1-(3x2/l2) = 00.
x2=l2/3.
x2=l2/3.
Venkatesh said:
8 years ago
Shear force is the partial derivative of bending moment so to obtain shear force the given bending moment is differentiated with respect to x and submit the given options so that you should get zero.
Ebeyehu said:
8 years ago
The derivation of the moment is always shear having this idea we can derivate and we obtain dm/dx =a (1-3x*x/l*l) say this equation is zero and we will get 1-3x*x/l*l =0 from this x=l/3thepower of half.
Maneesha said:
8 years ago
Give me the correct explanation.
Kashi said:
1 decade ago
Maximum bending moment occurs at zero shear force*.
d(M)/dx = 0 (for maximum bending moment).
on differentiating above equation you get option C.
d(M)/dx = 0 (for maximum bending moment).
on differentiating above equation you get option C.
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