Velocity from Position (Demo)
This Illumination demonstrates the calculation of the instantaneous velocity from a position vs. time graph. Each time you click "Go", the applet draws a new graph showing the position of an object as a function of time. In addition, a point on the graph is expanded and a tangent line to the curve at that point is shown. By clicking the "Step" button you can follow the calculation as the coordinates of two points on the tangent line are revealed, and the velocity computed. Note the answer is rounded off to one digit past the decimal point.