$(a)$ Which type of motion is represented by the velocity-time graph shown below?
$(b)$ Name the physical quantity which can be calculated by the area of rectangle $OABC$.
$(c)$ What does the straight line $AB$ represent?

(N/A) The velocity-time graph shows a constant velocity over time,which represents uniform motion.
$(b)$ The area under a velocity-time graph represents the displacement of the object. Therefore,the area of rectangle $OABC$ represents the displacement.
$(c)$ The straight line $AB$ is parallel to the time axis,which indicates that the velocity of the object remains constant over time,representing uniform motion.