One of the hazards of prolonged weightlessness on long space missions is bone and muscle loss. To combat this problem, NASA is studying a human-powered centrifuge, like the one shown in FIGURE 6-61. In this device, one astronaut pedals a suspended, bicycle-like contraption, while a second astronaut rides standing up in a similarly suspended platform. If the standing astronaut moves with a speed of 2.7 m/s at a distance of 2.9 m from the center of the device, what is the astronaut's centripetal acceleration? Give your answer as a multiple of g, the acceleration due to gravity on the surface of the Earth.