So I got this from ChatGPT but I don't see where this is at all. Is it a hallucination? Or is it a new feature or from a specific add-in I don't have? I have Premium and Simulation.

2. Using a Variable Coefficient via a Motion Function

If you want full control over friction vs. velocity (e.g., μ = 0.3 + 0.1 · exp(–v²)), you can:

• Define Contact between bodies.
• In the PropertyManager for the Contact, instead of entering a constant for μ, click the fx button to enter an Expression.

• In the expression, you can use variables like velocity (usually relative velocity between surfaces).
  This is done through the Motion Function Builder, using syntax like:

  cppCopyEditμ = 0.3 + 0.2 * exp(-VEL("Part1","Face1","Part2","Face2")^2 / 0.1)
  

• SolidWorks Motion passes the velocity into the equation each time step, so your coefficient changes dynamically.