In this simulation, a position-time graph is shown for a soccer ball that is thrown directly upwards and then falls back to the ground. In this case, the action takes place on the Moon, so the free-fall acceleration is not the same as on Earth. Your challenge is to match the graph by setting the soccer ball’s initial velocity and the constant free-fall acceleration.

The vertical axis of the graph is the vertical position of the soccer ball, and the horizontal axis is time. The graph goes through exact grid points at the beginning, as the ball reaches its maximum height, and as the ball returns to the ground and stops. These grid point values should help you to calculate both the initial velocity and the acceleration. (You could look up the Moon’s free-fall acceleration, but there are different reported values, so you may not find the one we used. Better do the math.) Since there are two unknown values, you will need to use two equations. A useful value to know is the velocity of the ball when it reaches its maximum height. You can determine that value without calculation. Review the section on linear motion equations if you are not sure how to start.

Enter the initial velocity to the nearest 0.1 m/s and the acceleration to the nearest 0.1 m/s² and press GO. The soccer ball will move, and its position will be graphed. Press RESET to start over.