Algodoo

Should the plot be something other than a pure sinewave during stick/slip? I can't seem to get the mass to stick/slip by adjusting those parameters (unliess I'm not understanding what I'm seeing). Could you give known values that will definitely cause the stick/slip process?

BTW - Excellent scene! Nice controls, etc.

Reduce the plane velocity to below 0.05 and you will see the sine wave change to a saw tooth. Alternatively, you can decrease the spring rate or increase the mass until you see a saw tooth. The sine wave may also be stick-slip, but once the wave changes to a sine wave the oscillation occurs at the natural frequency of the spring mass system relatively independent of the plane velocity. I'm no expert on stick-slip, so additional comments or corrections are welcome.

I now got the sawtooth, but it's only because the friction increases on the "push" stroke, and decreases on the "pull" stroke. If you watch the friction slider of the mass, you will see it change with direction. I do not get a true slip/stick "chatter" that I expect, such as that you get when you run a piece of chalk across a blackboard and you get that annoying chattering sound. Maybe that effect is impossible to acheive with Algodoo (?).

BTW - I learned about stick/slip MANY years ago when I first heard about it on the old "Watch Mr. Wizard" TV science show for kids (yes, I'm dating myself!).

It might just be your point of reference. The plane is moving left. The box is sticking to the plane during the downward slope of the saw tooth and slipping during the rising slope. The code applies static friction when the box velocity matches the plane velocity within 1%, otherwise it uses dynamic friction. In real life, stick slip is relatively independent of velocity once you get past some critical velocity. A violin does not change frequency with the speed of bowing. The screeching of chalk across the blackboard does not change much with speed.

Okay, NOW I get it.... The plane is moving at a constant velocity and the mass is sticking/slipping as the plane moves under it. That's the thing that I missed before, and now it all makes sense. THANKS!