Whats the period of greg's golf ball in orbit in minutes? Mass of earth is 6.0 x 10^24 kg. and its radius is 6.0 x 10^6 m.

(Greg hits a golf ball and says "that gotta be the lowest orbit on record".)

Assume your 6000 km is the radius of the ball's orbit around the Earth, NOT the radius of the golf ball. r is approximately the radius of the Earth in this case

GM/r^2 = V^2/r
(gravitational force)/mass = dentripetal acceleration
V^2 = GM/r
G is the universal constant of gravity, M is the mass of the earth and V is the velocity of the ball. Solve for V, and then get the period P from
V*P = 2 pi r