#### Strenght of Materials

16

The hoop stress in a riveted cylindrical shell of diameter (d), thickness (t) and subjected to an internal pressure (rho) is (where eta = Efficiency of the riveted joint)

A. (rhod)/(teta)
B. (rhod)/(2teta)
C. (rhod)/(4teta)
D. (rhod)/(8teta)

17

If the modulus of elasticity for a given material is twice its modulus of rigidity, then bulk modulus is equal to

A. 2C
B. 3C
C. (2C)/(3)
D. (3C)/(2)

18

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

19

When a closely-coiied helical spring of mean diameter (D) is subjected to an axial load (W), the deflection of the spring (delta) is given by (where d = Diameter of spring wire, n = No. of turns of the spring, and C = Modulus of rigidity for the spring material)

A. (WD^3n)/(Cd^4)
B. (WD^3n)/(2Cd^4)
C. (WD^3n)/(4Cd^4)
D. (WD^3n)/(8Cd^4)

20

The strain energy stored in a hollow circular shaft of outer diameter (D) and inner diameter (d) subjected to shear stress is

A. (tau^2)/(2C) ((D^2 - d^2)/(D))x Volume of shaft
B. (tau^2)/(2C) ((D^2 + d^2)/(D))x Volume of shaft
C. (tau^2)/(4C) ((D^2 - d^2)/(D))x Volume of shaft
D. (tau^2)/(4C) ((D^2 + d^2)/(D))x Volume of shaft