Final answer:
Using the momentum formula, momentum (p) = mass (m) × velocity (v), and the given values, we calculated the athlete's mass to be 65 kg.
Step-by-step explanation:
An athlete running at 8 m/s has a momentum of 520 kg·m/s. To find her mass, we can use the formula for momentum, which is momentum (p) = mass (m) × velocity (v). We can rearrange this formula to solve for mass (m):
m = p / v
By substituting the given momentum (520 kg·m/s) and velocity (8 m/s), we can calculate the athlete's mass:
m = 520 kg·m/s / 8 m/s = 65 kg
Therefore, the mass of the athlete is 65 kg, which corresponds to option a) 65 kg.