The resultant is a single force having the same overall effect as the combined forces. Add forces acting in the same direction and subtract opposing forces along a straight line. For Higher tier, use head-to-tail scale diagrams to find two-dimensional resultants, resolve forces into components and show equilibrium with a closed vector shape. Example: [HT] Explain equilibrium in a closed head-to-tail force diagram. The endpoint returns to the start, so the resultant is zero. Check your reasoning.