Astronauts in space are apparently weightless. Weightlessness has many challenges because objects float in space. Objects cannot be placed down and movements are difficult. You decide to introduce artificial gravity in space from spinning. To do so, you attach a ring to the International Space Station and set it to spin about its center. How many revolutions per minute must the ISS (with a 109 m diameter ring attached to it) make about its center to produce artificial gravity equal to Earth's gravity at the surface of the ring?