Diagram above shows that four forces of magnitude 2N, 4N, 5N and 8N are acting on point O. All the forces are perpendicular to each others. What is the magnitude of the resulatant force that acts on point O?

**Answer**:

The resultant force of the horizntal component = 5 - 2 = 3N to the right

The resultant force of the vertical component = 8 - 4 = 4N acting downward.

Therefore, the magtitude of these 2 force components,

|F| = \sqrt {3^2 + 4^2 } = \sqrt {25} = 5