We consider first three eigen modes for blade vibration under three blade holding conditions: clamped, hinged and guided, the other end being considered as free. Also, we will consider two different cross-section: solid circular and hollow circular. Calculate the 18 eigen frequencies for the following geometric conditions: 20 cm long, solid: 20 cm diameter; hollow: 30 cm OD with the same mass as the solid one. The blade is made of The material he told us to use is Inconel 738 alloy.