Consider a long steel bar under a tensille due to force `F` acting at the edges along the length of the bar (figure). Consider a plane making an angle `theta` with the length. For what angle is the tensile stress a maximum?

Options

A. `30^(@)`
B. `45^(@)`
C. `60^(@)`
D. `90^(@)`

Answer

D

Explanation

Tensile stress `= (F_(bot))/(A') = (F sin theta)/(A//sin theta) = (F)/(A) sin^(2) theta`
for tensile stress to be maximum,
`sin^(2) = 1 rArr sin theta = 1 rArr theta = (pi)/(2)` or `theta = 90^(@)`