When you click the play button, the box will begin sliding to the right. Kinetic friction will slow the box and eventually cause it to stop. Predict the shape of the distance, velocity and acceleration graphs. Run the simulation to check your prediction.
Next, you can make some quantitative predictions.
Set an initial velocity for the box. This will be the velocity of the box when you start the simulation. Also set a coefficient of kinetic friction. Set a mass for the box. Predict how far the box will slide based on these parameters. Check your prediction using the simulation.
How would increasing the mass change the motion? Make a prediction listing all the things that will change on the simulation, and then check your prediction.