Mars has surface gravity 0.39 g or about 3.9 m/s2, radius r = 3332 km and a rotation period of 24 hr. 37.38 min.
(a)What is the orbital velocity at distance r?
(b)What is the escape velocity from the surface?
(c) For communication, astronauts on Mars may use a synchronous satellite. At what distance R (in Mars radii) would it orbit? (Use a calculator with cube roots or 1/3 powers.)

Question

Mars has surface gravity 0.39 g or about 3.9 m/s2, radius r = 3332 km and a rotation period of 24 hr. 37.38 min.
(a)What is the orbital velocity at distance r? 
(b)What is the escape velocity from the surface?
(c) For communication, astronauts on Mars may use a synchronous satellite. At what distance R (in Mars radii) would it orbit? (Use a calculator with cube roots or 1/3 powers.)