FAST BALLS
First click on "Load blue ball", then on "(re)start ...

First click here: Load blue ball Load red ball

For each ball: Where will the ball be after 10 seconds? After what time will x = -80?

Is this motion linear or not? How can you find out?
Take readings and make a table of the position after 0, 1, 2, 3, 4, seconds. Show that there is NOT a common difference, or constant rate of change, but that the second difference is constant.
Use the data to find the formula for each animation and use it to answer the original questions:

Where will the blue ball be after 10 seconds?    

After what time will the red ball be at x = -80?