Contact Problems on a Slightly Viscoelastic Medium

Only the case of lubricated motion will be considered. This is conveniently simple, for purposes of illustration. The frictional case is discussed by Golden (1979b). Following in the spirit of Sects. 3.7, 5.3, we put 

We now write down (7.1.15 b) for the frictionless case, again dropping the subscript on kx.  

We therefore have an explicit expression for which immediately gives the form of 

The function l(t) will be causal, in the sense defined in Sect. 1.10. This is clear on physical grounds. It also follows from the kind of argument formulated in 

10 if we restrict the discussion to the subsonic case. For subsonic velocities, /(co) can be expanded as a Taylor expansion in the velocity, where each term is a rational function of the moduli, as required by the argument in Sect. 1.10. We will see in the next section that the situation becomes more complex above the subsonic region. Taking the inverse Fourier transform of (7.2.3 a) gives 

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