DYNAMICS OF SLIDING IN A SPRING BLOCK EXPERIMENT

An experiment has been performed to investigate the intermittent motio n of a simple spring-block setup. We show that in the limit of continu ous sliding the measured power spectrum of the block position is surpr isingly well described by a simple Langevin equation for a harmonic os cillator. Furthermore, we investigate the correlations in characterist ics of the motion and find strong correlations in the ''sticking'', wh ereas we find much weaker correlations in the ''slipping''. For stick- slip motion the interpretation is that the static friction is governed by local surface properties, whereas the dynamic friction is largely a stochastic process.