1.

If a box has equal and opposite forces acting on it, will the box accelerate?

Yes

No

2.

The two forces acting on a skydiver are and air .

gravity; resistance

inertia; acceleration

3.

Unbalanced forces always result in .

motion

friction

1. B)NO

2. A) Gravity; resistance

3. A) Motion

Explanation:

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.  

there is none because earth is stationary and flat.