3. A steel pipe of outside diameter 20 mm and thickness 3 mm is
deflected by 3 mm when used as a beam supported at its ends, 1
m apart, and subjected to a central load of 170 N. Find the
buckling load when the pipe is used as a column with hinged
ends. What is the maximum lateral deflection of this column
before the material attains the yield stress of 250N/mm??​