A graph with horizontal axis time (seconds) and vertical axis position (meters). An orange line runs straight upward from 0 second zero meters. A concave blue line runs upward from the same point.

Maia says that both lines on this position vs time graph show acceleration. Is she correct? Why or why not?

No, she is not correct. Acceleration is the rate of change of velocity, which is the rate of change of position. The orange line shows a constant rate of change of position, which is a constant velocity, and therefore no acceleration. The blue line shows a changing rate of change of position, which is a changing velocity, and therefore acceleration.