According to Newton’s first law of motion, when will an object at rest begin to move? when its inertia decreases to zero when an unbalanced force acts upon it when the action and reaction forces are equal when two equal and opposite forces act upon it

Option b

Explanation:

This is a nice and simple question!

Consider Newton's first law of motion. It states that an object at rest will remain at rest until acted upon by an unbalanced force. That being said the reverse is applicable as well, an object in motion will remain in motion unless acted upon by an unbalanced force.

Thus, according to Newton's first law of motion, an object at rest begins to move when an unbalanced force acts upon it.

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.