Rotating Space Stations. One problem for humans living in outer space is that they are apparently weightless. One way around this problem is to design a space station that spins about its center at a constant rate. This creates "artificial gravity" at the outside rim of the station. (a) If the diameter of the space station is 800 $\mathrm{m}$ , how many revolutions per minute are needed for the "artificial gravity" acceleration to be 9.80 $\mathrm{m} / \mathrm{s}^{2}$ (b) If the space station is a waiting area for travelers going to Mars, it might be desirable to simulate the acceleration due to gravity on the Martian surface $\left(3.70 \mathrm{m} / \mathrm{s}^{2}\right) .$ How many revolutions per mimute are needed in this case?