| Acceleration Vector: Use this tool to give body elements constant acceleration during Run mode. To attach the acceleration vector, click on the target body, then drag out the vector in the direction and to the length you desire. The acceleration vector appears as a thin blue line. You can later change the length and direction of the acceleration vector by resizing it, or by setting the strength (i.e., magnitude, in kg/s2) and direction (degrees) in the vector's Properties Box. You can only attach one acceleration vector to any single body. In the Properties Box, you can also set the label for the acceleration vector (default is a) and show (or not show) the vector's label, strength (i.e., magnitude), and direction (default is to show only the label). Placing a acceleration vector disables the force vector and impulsive forces tools, and the background gravitation source property.