A Parallelogram Law Puzzle?

📌 CONCEPT: The Parallelogram Law is a method used to determine the resultant of two vectors by considering the forces acting on a point as adjacent sides of a parallelogram, where the triangle formed by these forces and their resultant is a right-angled triangle.

📐 RULE / FORMULA: According to the Parallelogram Law, the magnitude of the resultant force (R) is given by the formula R = √(a² + b²), where a and b are the magnitudes of the two forces acting on the point.

💡 WORKED EXAMPLE: If two forces of magnitudes 6 N and 8 N act on a point, such that the triangle formed by these forces and their resultant is a right-angled triangle, then the magnitude of the resultant force is R = √(6² + 8²) = √(36 + 64) = √100 = 10 N.

⚠️ COMMON MISTAKE: Students often forget to use the formula R = √(a² + b²) and instead try to find the resultant by adding or subtracting the magnitudes of the two forces, which is not correct.