If an object has two forces acting on it how can the next force equal 0

If the forces are equal and in opposite directions, the net force will equal zero.

Consider a tug-of-war team. If they are pulling with equal forces against each other, the red cloth on the rope will not move.

F = ma

The cloth is not moving, so a = 0 and the net force F = 0.

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

particle   p is an electron and particle q is a neutron