at what speed must the surface of a space station rotate for an astronaut on the inside surface to experience equal half of his weight on Earth. The

at what speed must the surface of a space station rotate for an astronaut on the inside surface to experience equal half of his weight on Earth. The radius is 1000M?

Calculate the escape speed of the planet mars with a radius of 3.4 million meters and a mass of 6.4 x 1023 kg.?