Question

Question 11

Part A)

What is the stress within the girder?
Express your answer to two significant figures and include the appropriate units.

stress

Part B)

A sign (mass 2400 kg ) hangs from the end of a vertical steel girder with a cross-sectional area of 0.013 m2 . Ignore the mass of the girder itself. The elastic modulus for steel is 2.0×1011N/m2.

What is the strain on the girder?
Express your answer to two significant figures.

strain =  
Part C)

If the girder is 7.60 m long, how much is it lengthened?
Express your answer to two significant figures and include the appropriate units.

Δℓ =  

Answer 1

Modulus of Elasticity for Steel = 200 * 10^9 N / m^2

(a) What is the stress within the girder?

stress = Force / cross -sectional area = (2400*9.81) / 0.013 = 1.8*10^6 N / m^2.............ans

(b) What is the strain on the girder?

Strain = Stress / Young's modulus = (1811076.92) / ( 200* 10^9) = 9.1* 10^-6...............ans

c) If the girder is 7.6 m long, how much is it lengthened?

elongation = strain x length = 7.546155* 10^-7 * 7.60 = 6.9*10^-5 m ...............ans

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