Dynamics of sliding in a spring-block experiment

An experiment has been performed to investigate the intermittent motion of a simple spring-block setup. We show that in the limit of continuous sliding the measured power spectrum of the block position is surprisingly well described by a simple Langevin equation for a harmonic oscillator. Furthermore, we investigate the correlations in characteristics of the motion and find strong correlations in the 'sticking' whereas 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.