Sliding Speed and Friction

In this section the interaction of sliding speed and friction, in particular the interpretation of the instrumental displays in the measurement of motion, will be examined more closely than it was in Sections 8.3 and 8.4. We are interested specifically in the reliable determination of with an apparatus that employs elastic coupling of the 

The behavior over the entire range of speeds shown in Fig. 8-16 is discussed in Chapter 9. 

To find how the critical velocity at which the driven surface is translated affects the transition from intermittent to smooth sliding requires that the theory of stick-slip be extended to include the empirical fact that the magnitude of the coefficient of kinetic friction is a function of the velocity with which the rider rubs against the countersurface. Using the approach of Brockley, Cameron and Potter [15], the expression for the coefficient of kinetic friction is written as 

Details of the solution of this equation are given by Brockley, Cameron and Potter. A usably adequate approximation for the amplitude of vibration is 

In Fig. 8-17 the comparison of the results calculated by Brockley, Cameron and Potter [15] from Eqn 8-37 for three different sliding systems with the data they obtained experimentally shows the behavior of the critical velocity concept in stick-slip sliding and its confirmation by 

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