Example 3:

Example 3: A force of 11 pounds and a force of 6 pounds act on an object at an angle of 41° with respect to one another. What is the magnitude of the resultant force, and what angle does the resultant force form with the 11‐pound force (Figure  7)?

Figure 7
               Drawing for Example 3.

First, use the Law of Cosines to find the magnitude of the resultant force.

Next, use the Law of Sines.

Thus the resultant force is 16.02 pounds, and this force makes an angle of 14.24° with the 11‐pound force.