Instantaneous Acceleration - Applet Info

Motion Controls

• Setting the initial velocity. Click on the car and drag with the mouse to set the car's initial velocity vector (shown in magenta). If the car is not visible, because the Car check box is unselected, click on the yellow dot and drag. Subsequently, if you are in Position Space view (Velocity Space check box unselected), you can drag the car itself to a new starting position.
• Setting the car's acceleration. Click in the acceleration dial to set the car's acceleration (shown in orange). The car will move with this acceleration, and its velocity and position will change accordingly.

  To vary the car's acceleration, keep the mouse button depressed with the mouse pointer still in the acceleration dial and drag the acceleration vector. Releasing the mouse button will pause the motion. Clicking in the acceleration dial again, will resume the motion.

• Play, Replay, and Step. The motion will start automatically as soon as you click in the acceleration dial. To stop the motion, release the mouse button. When you click REPLAY, the car will be reset to its initial position, velocity, and acceleration. If you now click PLAY, the car will repeat its previous motion automatically without you having to steer the motion via the acceleration dial. Instead of PLAY, which shows the previous motion continuously, you can use STEP to view the previous motion step-by-step. PLAY/PAUSE is a toggle button that lets you pause and then resume the playing of the previous motion.

Display Controls (Check Boxes)

• Velocity Space. When this check box is unselected, you can view things so that the position space origin is at rest and the car is moving. The tail end of the velocity vector is attached to the car and therefore the velocity vector is shown moving with the car.

  When the Velocity Space check box is selected, you can view things so that the origin of velocity space is at rest with the car. The origin of position space and other points in position space (indicated by a background of dots) is shown moving relative to the car.

• Car. When this check box is selected, the car will be shown. If it is unselected, the car is replaced by a small black dot, visible only if no vectors are being displayed.
• Pos Path and Vel Path. When these check boxes are selected, the paths of the tips of the position and velocity vectors, respectively, are shown, respectively, color-coded relative to these vectors.
• Grid. When this check box is selected, a position space coordinate grid is shown. If you are in the Position Space view (Velocity Space box unselected) while the Grid check box is selected, you can click on the applet window and drag all of position space, including the car, the coordinate grid, and origin of position space. If the control key is depressed while you drag, position space will not be dragged, i.e., the car will remain stationary relative to the applet window, but the coordinate origin of position space and the coordinate grid will be dragged. This corresponds to a change in coordinate system of position space. If you select the Position Vector check box, you can see how the car's position vector can be varied this way without changing the car's position.
• Position Vector, Velocity Vector, Accel #1, Accel #1. Selecting any of these check boxes will cause the respective vectors to be displayed. The difference between Accel #1 and Accel #2 is that the former shows the acceleration vector attached to the center of the car while the latter shows this vector attached to the tip of the velocity vector (as the velocity vector is shown attached to the tip of the position vector). Of course, the acceleration vector is shown also in the acceleration dial.

  The position vector is in cyan, the velocity vector in magenta, the acceleration vector in orange.

• Data #1 and Data #2. When one of these check boxes is selected, the values of time/velocity/acceleration or time/position/velocity, respectively, are displayed.