#### Strenght of Materials

6

When a body is subjected to a direct tensile stress sigma_x) in one plane accompanied by a simple shear stress (tau_(xy) the maximum shear stress is

A. (sigma x)/(2) + 1/2 sqrt(sigma_x^2 + 4 tau_(xy)^2)
B. (sigma x)/(2) - 1/2 sqrt(sigma_x^2 + 4 tau_(xy)^2)
C. (sigma x)/(2) + 1/2 sqrt(sigma_x^2 - 4 tau_(xy)^2)
D.  1/2 sqrt(sigma_x^2 + 4 tau_(xy)^2)

7
The bending equation is
A. M/I = sigma /Y = E/R
B. T/J = tau/r = (c theta)/(l)
C. M/Y = sigma/I = E/R
D. T/r = tau /J = (C theta)/(l)

8
The polar modulus for a hollow shaft of outer diameter (D) and inner diameter (d) is
A. pi/4 ((D^2 - d^2)/(D))
B. pi/16 ((D^3 - d^3)/(D))
C. pi/16 ((D^4 - d^4)/(D))
D. pi/32 ((D^4 - d^4)/(D))

9

Which of the following is the correct torsion equation?

A. M/I = sigma /Y = E/R
B. T/J = tau/R =( C theta)/(l)
C. M/R = T/J = (C theta)/(l)
D. T/ l = tau/J = (R)/(C theta)

10
The length of a conical bar is l, diameter of base is d and weight per unit volume is w. It is fixea at its upper end and hanging freely. The elongation of the bar under the action of its own weight will be
A. (Wl^2)/(2E)
B. (Wl^2)/(4E)
C. (Wl^2)/(6E)
D. (Wl^2)/(8E)`