Answer :
Answer: a) T= 7.95kip.in b) T'= 6.38kip.in c) a= 1°
Explanation:
a) ta = allowable shear stress= 12ksi
Using torsion formula
tm= ta= Tc/J tm = Maximum shear stress
12= T(0.75)/(π/2)(0.75^4). radius= d/2 = 1.5/2 = 0.75in
T= 12(π/2)(0.75^3)= 7.95kip.in
b) using torsion formula
tm= ta= T'c/J radius 2= d/2= 1.0/2 = 0.50in
12= T'(0.75)/(π/2)(0.75^4 - 0.5^4)
T'= 6.38 kpi.in
c) angle of twist = a = TL/JG L= 1ft= 12in
a = 6.38 × 12/(π/2)(0.75^4 -0.50^4)(11)(10^3)
a = 0.01745 rad = 1°