Final answer:
The minimum magnitude of the resultant of two concurrent forces occurs when the forces are aligned at an angle of 180° to each other, which results in the forces acting in opposite directions and partially cancelling out.
Step-by-step explanation:
The magnitude of the resultant of two concurrent forces is a minimum when the angle between them is 180°. When two forces are acting in exactly opposite directions, their effects partially cancel each other out, leading to a minimum resultant magnitude. This is opposite to when they are both acting in the same direction (0°), where they add up to give the maximum resultant. For example, if we have two forces of equal magnitude F acting concurrently, at 180° to each other, the resultant force would be 0. However, if they are at any other angle, the magnitude of the resultant force would be greater than 0. Specifically, at 180°, the resultant can be calculated using vector addition, F + (-F) = 0, which clearly yields the smallest possible resultant magnitude.