A real-world example in which two opposite quantities are added and have a sum of zero would be;
a) Descriptive answer: A seesaw with two children sitting on it. One child, 50 kg sits on the left side, pushing down with a force of 50 N. On the right side, another child, also 50 kg sits and pushes up with the same force.
b) Interpretation of graph required: Adding these points on the number line will lead to the point 0, indicating the balanced state of the seesaw.
c) Numerical expressions provided: Total force = F_left + F_right
Total force = -50 N + 50 N = 0 N
d) Graph representation given: The graphed representation would have the following values on the number line; -50 0 +50
What is the real-world example?
Since the children described above exert equal and opposite forces, the seesaw remains balanced and at rest. In this situation, the forces acting on the seesaw which is 50 N pushing down and 50 N pushing up can be represented as opposite quantities. Adding them together results in a sum of zero, indicating the seesaw's equilibrium state.
On a number line, we can represent the forces as points: Left side: -50, negative due to downward force, and on the Right side: +50, positive due to upward force.