Q1. A space station is constructed in the shape of a wheel 19 in diameter, with essentially all of its 1.3×10^5 mass at the rim. Once the station is completed, it is set rotating at a rate that requires an object at the rim to have radial acceleration, thereby simulating Earth's surface gravity. This is accomplished using two small rockets, each with 130 thrust that are mounted on the rim of the station.

Q2. How were gravity and motion of the planets viewed historically before Newton? Views from Aristotle, Galileo, and Kepler.