A student is conducting an experiment with a water rocket. The rocket is launched vertically up, and its velocity is tracked using a sensor. The expulsion of water accelerates it upward. When the water is fully expelled, the rocket briefly continues to ascend and then starts to fall. As the rocket descends, it accidentally hits a tree, which makes the sensor stop. The graph shows the velocity of the water rocket during its flight. When did the rocket attain its maximum acceleration?
