QUESTION 5 A 45kg machine is placed at the end of a 1.6m cantilever beam of the elastic modulus of 200x10 N/m? and cross sectional moment of inertia 1.6x10 m. As it operates, the machine produces a harmonic force of magnitude 125N. At what operating speeds will the machines steady state amplitude be less than 0.2mm?

Figure below shows an aircraft fighter. The wing of the aircraft may be modelled as a clamped wing with two lump masses at its centre and tip. The two masses represent the mass of the wing and the missiles. The equivalent model shown in the figure is used to estimate the first two natural frequencies of the wing and therefore the fuselage can be assumed rigid. 24EI If m1 = am, m2 = bm and bending stiffnesses of the beams are k where a = 9.7147 and b = 4.1873 and if w, and wz are the first and second natural frequencies of the system, w2/wz is: x, (t) x2(t) EI т, EI (m2) /2 1/2 3.2719 2.4236 1.3088 1.7692 4.7260