Correct Response: A. The area under a force versus displacement graph for a moving object is equal to the work done by the force on the object if the force is parallel to the displacement. This is a measure of the change in energy of the system. The slope of the line tangent to a velocity versus time graph (B) is acceleration, which equals the rate of change in velocity, not energy. The area under a force versus time graph (C) equals impulse, which also equals the change in momentum, not energy. The slope of the line tangent to a momentum versus time graph (D) equals the rate of change in momentum, which equals force, not energy.
