A 1000-n weight is hanging from a 2.0 m long aluminum rod. A 500-n weight is hanging from a 1.0 m long aluminum rod. The two aluminum rods have different cross sectional areas. Which rod is under the greater tensile stress?

Respuesta :

Answer:

Both rod have the same tensile stress

Explanation:

Given information,

The weight first rod, [tex]W_{1}[/tex] = 1000 N

The length of first rod, [tex]l_{1}[/tex] = 2.0 m

The weight second rod, [tex]W_{2}[/tex] = 500 N

The length of second rod, [tex]l_{2[/tex] = 1.0 m

The equation of tensile stress, σ = [tex]\frac{F}{A}[/tex]

where

σ = tensile stress (N/[tex]m^{2}[/tex] or Pa)

F = Force (N)

A = Area (N/[tex]m^{2}[/tex] or Pa)

so

σ1 =  [tex]\frac{W_{1} }{A_{1} }[/tex], A = 2πl

    = [tex]\frac{1000}{2\pi(2) }[/tex]

    = [tex]\frac{250}{\pi }[/tex] N/[tex]m^{2}[/tex]

now calculate σ2

σ2 =  [tex]\frac{W_{2} }{A_{2} }[/tex]

     = [tex]\frac{500}{2\pi(1) }[/tex]

     = [tex]\frac{250}{\pi }[/tex] N/[tex]m^{2}[/tex]

σ1/σ2 = [tex]\frac{250}{\pi }[/tex] / [tex]\frac{250}{\pi }[/tex]

σ1/σ2 = 1

σ1 = σ2

Hence, the tensile stress of first and second rod are the same.