PHYS 1007 Lecture Notes - Lecture 20: Modulus Guitars, Viscosity, Circular Motion
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Viscous low viscous force fv: fv = {eta} ( v/d)a, eta is coeicient of viscosity (called a poise" measured in pa s, in brackets is the velocity gradient perpendicular to the low, a is the area. Volume low rate given by poiseuille"s law: q = v/ t = (pi/8)( p/l)(1/{eta})(r4) Second bracket is pressure drop over distance l. Viscous force on spherical objects: fv = 6pi{eta}rv. E = stress/strain = (f/a)/( l/l: shear modulus. L is perpendicular to l: bulk modulus. This moion can be modeled by simple harmonic moion. Moion that can be described by sin & cos. If you can idenify a vibraion as shm, then all of the formulae can be applied. Presence of restoring force (a force that increases linearly with displacement from equilibrium. At x=0, there is no force exerted and it is the equilibrium posiion. As we pull object away, restoring force = f = -kx.