Problem 6.7: for a bronze alloy, the stress at which plastic deformation begins is 275 mpa (40,000 psi), and the modulus of elasticity is 115 gpa (16.7 ×)what is the maximum load that may be applied to a specimen with a cross-sectional area of 325 mm2(0.5 in.2) without plastic deformation? (b)if the original specimen length is 115 mm (4.5 what is the maximum length to which it may be stretched without causing plastic deformation?

a) P = 20000 lbf

b) ΔL = 0.01 in

Explanation:

a) We apply the following formula

σ = P / A    ⇒   P = σ*A  ⇒  P = (40000 PSI)*(0.5 in²) = 20000 lbf

b) We use the equation of Hook's Law:

ΔL = (P*L) / (A*E)

⇒   ΔL = (20000 lbf  *4.5 in) / (0.5 in² * 16.7 ×10∧6 PSI) = 0.01 in

the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true?

a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of

5

9

degree celsius.

a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit.

a temperature increase of

5

9

degree fahrenheit is equivalent to a temperature increase of 1 degree celsius.

a) i only

b) ii only

c) iii only

d) i and ii only