Final answer:
When two forces act in the same direction, they add together, resulting in a greater overall force that can, for example, make it easier to move a heavy object.
Step-by-step explanation:
When two forces act in the same direction, their effects add up, resulting in a larger overall force. This can be illustrated by imagining you and a friend trying to move a heavy box. If you both apply a force in the same direction, the resultant force on the box is the sum of your individual forces, making it easier to move the box. If, on the other hand, the forces were applied in opposite directions, the resultant force would be the difference between these two forces, according to which direction is assigned as positive. This reflects a basic principle in physics that forces are vectors and thus adhere to vector addition. It is important to note that this concept is different from Newton's third law, which states that for every action, there is an equal and opposite reaction, but this law refers to forces between two different bodies, rather than the cumulative effect of forces acting on the same body in the same direction.