Explanation:
When the forces acting on an object are balanced , there is no change in the object's motion.
A force acting on a resting object can cause the object to move.
On Earth, gravity pulls all objects toward the ground.
When a force acts in the opposite direction of another force, the forces counteract each other.
More than one force acting on a falling object can reduce its downward acceleration
Air resistance is caused by molecules of air pushing against a moving object
A hydrogen atom has 0 charge because its two constituents are oppositely charged; and understand p + q as the number located a distance |q| from p, in the positive or negative direction depending on whether q is positive or negative.
Those are called isotopes,
the answer is 3.
each element has its own unique number of protons (atomic number) but a different number of neutrons can be shown in example number 3.