Why can scientists ignore the gravitational force when studying the physics of an atom?

Scientists can ignore the gravitational force because the electrical force between protons and electrons in the atom is millions of times stronger than the gravitational force between the protons and electrons. The gravitational force is insignificant for masses as small as the proton and electron.

Explanation:

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.