Physics questions i need help with please?

4) A cylindrical steel rod 0.50 m long and 1.0 cm in radius


is subjected to a tensile force of 1.0 × 104 N.


a What is the tensile stress?


b What is the tensile strain?


c By what amount does the rod stretch?





5) A cylindrical rod of cast iron has a diameter of 8.0 cm.


What weight can it support if it is not to exceed 40% of


the compressive strength?





6) A uniform concrete beam has a mass of 1.0 × 104 kg


and a length of 24 m. It is supported at the ends by two


vertical steel cables each of 3.0 cm in radius, as shown


in Figure 7.54. An additional load of 1.2 × 104 kg is


placed 2.5 m from one of the cables. What is the strain


in each cable?

Physics questions i need help with please?
4)


a)Tensile stress


TS= F/A


F= 1.0 E+4 N


A= pi(1E-2)^2=3.14 E-4 m^2


TS=F/A=31.83 E+6


b)


Tensile Strain


S= dL/L


S= 1.515 E-4 (do part (c))


c) dL=?


Yong's Modulus YM = TS/S=


YM for Steel = 210 E+9








S= TS/YM= 31.83 E+6/ 210 E+9


S= 1.515 E-4





S=dL/L


dL=SL= 1.515 E-4 x 0.5=7.58 E-5 m


dL=0.0758 mm





The rest is similar.