Download of SimMotion 1.0 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. The application lies within Education Tools, more precisely Science. This free Mac application is an intellectual property of Praeter Software.
From the developer:
SimMotion produces rich graphs to help you explore motion by changing various parameters. It lets you explore the fundamental meaning of velocity, acceleration, and position. You can set the initial parameters of velocity, acceleration, or position to any value in x- or y-direction and then see the resulting motion. You can even change parameters, such as acceleration and mid simulation to see the effect.
You may want to check out more software for Mac, such as Gee, Arcade Math Blocks or NLVM, which might be related to SimMotion.