(Solved): V. A compressed bar has a circular cross section as shown in the figure(radius \( r=2 \mathrm{dm} ...

V. A compressed bar has a circular cross section as shown in the figure(radius \( r=2 \mathrm{dm} \), length \( l=2 \mathrm{~m} \) ), it is fixed to the ground. Young's modulus is \( E=150 \mathrm{GPa} \). What is the critical load for buckling?(20 points)