Page 243 - Thomson, William Tyrrell-Theory of Vibration with Applications-Taylor _ Francis (2010)

230 Lagrange’s Equation Chap. 7
7-6 The four masses on the string in Fig. P7-6 are displaced by a horizontal force F.
Determine its equilibrium position by using virtual work.

F Figure P7-6.
7-7 A mass m is supported by two springs of unstretched length Tq attached to a pin and
slider, as shown in Fig. P7-7. There is coulomb friction with coefficient ¡jl between the
massless slider and the rod. Determine its equilibrium position by virtual work.

Figure P7-7.
7-8 Determine the equilibrium position of and m2 attached to strings of equal length,
as shown in Fig. P7-8.

Figure P7-8.
7-9 A rigid uniform rod of length / is supported by a spring and a smooth floor, as shown
in Fig. P7-9. Determine its equilibrium position by virtual work. The unstretched
length of the spring is h/4.

.1 Figure P7-9.
7-10 Determine the equation of motion for small oscillation about the equilibrium position
in Prob. 7-9.
7-11 The carpenter’s square of Prob. 7-3 is displaced slightly from its equilibrium position
and released. Determine its equation of oscillation.