These simulations are designed to give feedback to the users.

1. Adding mass to an object increases size, or shows extra stuff being added.
2. Velocity graphs have green lines corresponding to green velocity arrows.
3. Vectors increase in size as sliders are moved.

The simulations are designed to encourage prediction

1. The graphs and strobe diagrams are turned off when reset is pressed
2. Some simulations allow saving the current graph for comparison purposes