1) Planet Zero has a mass of 5.0*10^23 kg and a radius of 2.0*10^6 meters. What is the acceleration of gravity on planet zero?
2)Phobos, a satellite of Mars, has a radius of 11km and a mass of 10^16 kg. Its a bit lumpy, but let's assume its spherical to get a doable problem.
(a) What is G on Phobos?
3)Find the force of gravity between you and your pen if the writing device has the mass of 5.6 grams...estimate the difference.