Will knows that the gravitational pull of Mars is less than the gravitational pull of Earth. When he lands on Mars, his mass will be

i think it will "Equal to 75 Kg"

Explanation:

object/person remains same, his mass is somewhere, so it would remain same everywhere. Only Weight of a person changes with gravity

hope i helped

-lvr

i believe it is c.) 1575 j.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.