Suppose engineers built a rotating space station similar to Space Station V from the film *2011: A Space Odyssey*, but with multiple concentric rings where astronauts can live.

        ____________
       /  ____c___  \
      /  /  __b_  \  \
     /  /  /  a \  \  \
    /  /  /      \  \  \
    \  \  \      /  /  /
     \  \  \____/  /  /
      \  \________/  /
       \____________/

Ring `a` is 10 meters from the center, ring `b` is 20 meters from the center, and ring `c` is 30 meters from the center.

- If the station is set to rotate at a speed where the gravity within ring `b` is identical to Earth's gravity and the rings rotated together, would the gravity in rings `a` and `c` be significantly stronger or weaker?
- If the concentric rings could rotate freely, would rings `a` and `c` need to rotate faster or slower than ring `b` to ensure that the gravity at each ring had identical strength?