Final answer:
The mass of the runner is 3 kg, calculated by dividing the force produced (36 N) by the acceleration (12 m/s²) using Newton's second law of motion.
Step-by-step explanation:
The mass of the runner can be determined using Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration (F = m × a). Given that the force produced is 36 N and the acceleration of the runner is 12 m/s2, the mass (m) can be calculated by rearranging the equation to m = F / a.
Therefore, the mass of the runner is: m = 36 N / 12 m/s2 = 3 kg.