The deltoid muscle connects the humerus to the shoulder blade and facilitates out stretching of the arm as shown in the figure. The humerus is connected to the shoulder blade with a ball and socket joint. Assume the equivalent weight (W) of the arm to be 30 N and acts vertically down at a horizontal distance of 30 cm.
Assume that the deltoid muscle is connected to the humerus at a distance of 15 cm and makes an average angle of 20° with the horizontal. The magnitude of tension in the deltoid muscle is _______ N.