Let a steel bar of length '\(l\)', breadth 'b' and depth 'd' be loaded at the centre by a load 'W'. Then the sag of bending of beam is (Y = Young's modulus of material of steel)
1
\(\dfrac{W l^3}{2 bd^3 Y}\)
2
\(\dfrac{W l^3}{4 bd^3 Y}\)
3
\(\dfrac{W l^2}{2 bd^3 Y}\)
4
\(\dfrac{W l^3}{4 bd^2 Y}\)