Strenght of Materials

11

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

12
When a closely-coiled helical spring of mean diameter (D) is subjected to an axial load (W), the stiffness of the spring is given by
A. `(Cd^4)/(D^3 n)`
B. `(Cd^4)/(2D^3 n)`
C. `(Cd^4)/(4D^3 n)`
D. `(Cd^4)/(8D^3 n)`

13

The relation between modulus of elasticity (E) and modulus of rigidity (C) is given by

A. `C = (mE)/(2(m+1))`
B. `C =(2(m+1))/(mE)`
C. `C = (2mE)/(m+1)`
D. `C =(m+1)/(mE)`

14

The pull required to shear off a rivet, in double shear, per pitch length is

A. `pi // 4 xx d^2 xx sigma_t`
B. `pi // 4 xx d^2 xx tau`
C. `pi // 2 xx d^2 xx sigma_t`
D. `pi // 2 xx d^2 xx tau`

15
According to Euler's column theory, the crippling load for a column of length (l) with one end fixed and the other end hinged, is


A. `(n^2 EI)/(l^2)`
B. `(n^2 EI)/(4l^2)`
C. `(2n^2 EI)/(l^2)`
D. `(4n^2 EI)/(l^2)`