3- A 3 m column has a circular solid cross section whit d= 30 cm, one of the ends of the column is fixed and other end is free. Take the compressive yield stress as 35 MN/m², the Rankine constant 1/4000 and E= 20 GN/m². Determine: (a) The slenderness ratio.. (b) The Euler crippling load. (c) The Rankine crippling load.