Question

deena made a chart to summarize features of a velocity vs. time graph for objects with constant acceleration and objects with constant velocity.

constant acceleration	constant velocity
find displacement by subtracting the area of the triangle from the area of the rectangle under the line	find displacement using the area of the rectangle under the line only
find acceleration by finding the slope of the line	find velocity by locating the values plotted on the y - axis

which best describes deenas error?
o the line for constant velocity is not horizontal; it is diagonal and slopes downward.
o the area of the rectangle and the triangle under the line should be added together for constant acceleration
o find acceleration by finding the area of the rectangle above the line.
o find velocity by calculating the slope of the line.

Explanation:

Step1: Recall velocity - time graph concepts

For an object with constant acceleration on a velocity - time graph, the displacement is found by adding the area of the triangle and the area of the rectangle under the line (if applicable), not subtracting.

Step2: Analyze each option

• Option 1: The line for constant velocity is horizontal, not diagonal and sloping downward, so this option is incorrect.
• Option 2: For constant acceleration, the area of the rectangle and the triangle under the line should be added together to find displacement. This is correct as the total area under the velocity - time graph gives displacement.
• Option 3: Acceleration is found by the slope of the line, not the area of the rectangle above the line, so this option is incorrect.
• Option 4: For constant velocity, velocity is found by locating the values on the y - axis, not by calculating the slope of the line (slope is for acceleration), so this option is incorrect.

Answer:

The area of the rectangle and the triangle under the line should be added together for constant acceleration.