The normal stresses at a point in a steel member are σx = 8 ksi, σy = -4 ksi, and σz = 10 ksi. Using E = 29x103 ksi and ν=0.3, determine the normal strains at this point.

1. Steady state creep rate can be expressed by; És = Bo"e-/KT Apply this realtionship to the creep of a steel support rod in a boiler operating at 540 °C. The rod is stressed in tension to 40 MPa and its creep elongtion must not exceed 10 %. Using the data below, evaluate the constants in creep equation and estimate the lifetime of the rod.
2. The following rupture times were obtained for stress rupture tests on steel alloy.Establish the validity of the Larsen-Miller parameter.
3. determine the stress required to produce rupture in 2000hat 870C. Determine the rupture time at 760C for the same stress.

Let
H = {f : R → R | f(x) = ax + b; a, b ∈ R; a > 0}.
H1 = {f : R → R | f(x) = ax; a ∈ R; a > 0}.
H2 = {f : R → R | f(x) = x + b; b ∈ R}.
(a) Prove that H1 and H2 are subgroups of H.
(b) Determine whether each is a normal subgroup of H.