In this step, you will plot acceleration versus time on a graph, and
then calculate the area under that graph at various times. The values
of those areas will then be plotted on their own graph in the next step.
You will need to use the "Area" tool to accomplish this. Under "Tools" to the left, click on the "Area" button. A separate window, named "Estimate Area Under Curve," should pop up in which you will graph acceleration versus time and calculate the area under that curve for various times.
This tool is easy to use -- click the demo button for a quick demonstration of how to use it. If you're still having trouble understanding it, then try the "Help" button.
In the "Estimate Area Under Curve" window, plot acceleration versus time by entering -20 in the "y =" text field then pressing the "Graph Your Equation" button. On this graph, x will stand for the time variable in seconds.
Now you need to estimate the area under the graph of
To figure out what the car's speed is at that time, you need to subtract that area from the car's initial speed at time 0 seconds, which is given to be 88 ft/sec.
For example, if you want to find
the area under
After repeating this procedure for various times, you will have a set of points
representing an estimate of the car's speed versus time: at time
Next: Follow the "Velocity Curve" link to the left.