82. The Near Earth Asteroid Rendezvous (NEAR) spacecraft, after traveling 2.2 billion km, is meant to orbit the asteroid Eros with an orbital radius of about 25 km. Eros is roughly 40 km X 6 km X 6 km. Assume Eros has a density (mass/volume) of about 2.5 x 10^3 kg/m^3. 

(a) If Eros were a sphere with the same mass and density, what would its radius b?

(b) What would g be at the surface of a spherical Eros?

(C) Estimate the orbital period of NEAR as it orbits Eros, as if Eros were a sphere.