Question

How to calculate magnitude of force if force vector representation is given

Answer 1

Let's pretend that several forces act on a body.

Start to draw a polygon where each side of the polygon represents each force.

The length of each side should be proportional to the magnitude of the force it represents.

The direction of each side, indicated by an arrow, should be the same as the direction of the force it represents.

All of the arrows on your polygon should be clockwise.

If the polygon ends up as closed then the resultant force on the body is zero.

If the polygon does not close then draw a line to make it close. The length of this line will give you the magnitude of the resultant force. Put an anticlockwise arrow on this final line and the arrow will give you the direction of the resultant (net) force.