Final answer:
Ricardo's acceleration is calculated using the formula for acceleration a = (Vf - Vi) / t. Plugging in the values given, his acceleration is found to be 0.75 m/s².
Step-by-step explanation:
The student has asked to calculate Ricardo's acceleration given that he starts from rest, runs for 12 seconds, and reaches a final velocity of +9 m/s. To find the acceleration, we can use the formula for acceleration a = (Vf - Vi) / t, where Vf is the final velocity, Vi is the initial velocity (0 m/s in this case, since he starts from rest), and t is the time.
Substituting the given values into the formula, we get a = (9 m/s - 0 m/s) / 12 s = 9/12 m/s² = 0.75 m/s². Therefore, Ricardo's acceleration is 0.75 m/s².