3. If the normal stresses due to longitudinal and transverse loads on a bar are ?1 and ?2 respectively, the tangential component of the stress on an inclined plane through ?°, the longitudinal load is
5. A steel bar 20 mm in diameter simply-supported at its ends over a total span of 40 cm carries a load at its centre. If the maximum stress induced in the bar is limited to N/mm2, the bending strain energy stored in the bar, is