The Fall model shows the position and velocity of a ball that someone throws straight up in the air from a bridge.
Let's start by examining the velocity of the ball. We start with a stock for velocity, whose value is equal to the number on the slider for initial velocity. The velocity changes based on the "change in velocity" flow, which contains a term for acceleration due to gravity, -9.8 m/s2. The term speed is derived from the absolute value of velocity: Math.abs(velocity).
The position stock is controlled by the Initial Pos slider. The change in position flow is controlled by the velocity stock, which in turn controls position.
The pink graph and the purple table show position and velocity during the travels of the ball.