What is the charge of an atom with 20 protons and 18 electrons?

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

Find v(t), given acceleration a(t)=7j and initial velocity v(0)=k

How does the strength of the electrostatic force between an electron and a proton compare to the strength of the gravitational force between them?