Final answer:
If the wheel radius is doubled and the axle radius stays the same, it would take more than four athletes to turn the wheel.
Step-by-step explanation:
To find out how many athletes it would take to turn the wheel if the radius is doubled and the axle radius stays the same, we need to understand the concept of torque. Torque is the measure of a force's ability to cause rotational motion. When a force is applied to a lever arm, it creates a torque, which can be calculated using the equation:
Torque = Force x Distance
In this case, the force is exerted by the athletes and the distance is the radius of the wheel. Since the axle radius stays the same, it doesn't affect the torque. Therefore, if the wheel radius is doubled, the distance in the torque equation will also double. As a result, the torque will also double.
Since torque is directly proportional to the force applied, if the torque is doubled, the force applied by the athletes would also need to be doubled to maintain the same torque. Therefore, if it takes four athletes to turn the wheel when the radius is its original value, it would take more than four athletes to turn the wheel when the radius is doubled. So the answer is c. more than four athletes.