1. The problem statement, all variables and given/known data Assume you are agile enough to run across a horizontal surface at 8.50 m/s, independently of the value of the gravitational field. What would be (a) the radius and (b) the mass of an airless spherical asteroid of uniform density 1.10 310 3kg/m3 on which you could launch yourself into orbit by running? (c) What would be your period? (d) Would your running significantly affect the rotation of the asteroid? Explain. 2. Relevant equations 3. The attempt at a solution I have a few conceptual questions that pertain to this problem. I have a belief that the force with which the person running exerts on the surface is equal and opposite to the gravitational force that the asteroid provides, and is the reason why this person is running at a constant speed. However, I am not sure of why I have this suspicion. Also, I know this is a very elementary question, but how is it possible for a person to run if the ground provides and equal and opposite force to the force that the person exerts on the surface with there foot?