Answer:
Sample Response: The first part of the graph is a straight diagonal line and the second part of the graph is a straight horizontal line. The slope of the first part of the graph is positive, indicating that the cart increased in speed, and was therefore accelerating for the first four seconds. After the fourth second, the slope of the line is zero, indicating that the cart moved at a constant speed and did not accelerate any more because the fan was turned off.
Explanation: