A body can remain at its current position only if all the external forces acting on it sum up to zero. For a body to be in translational equilibrium, it is necessary that
When a 20 N weight is hung on a clothes line, the line sags as shown in diagram. Determine the tension in the clothes line.
Consider the equilibrium of the section of the rope where the mass is hung.
Horizontally, SFx = 0:
Vertically, SFy = 0:
Substitute back into earlier equation:
Because the three forces should add up to zero, they should form a closed vector triangle.
Using sine rule: