Two forces that act on an airplane wing are called the lift and the drag. Find the resultant of these forces acting on the airplane wing in Fig. 9.10.

Data from Example 6

Two persons pull horizontally on ropes attached to a car that is stuck in mud. One person pulls with a force of 500 N directly to the right, while the other person pulls with a force of 350 N at an angle of 40° from the first force, as shown in Fig. 9.8(a). Find the resultant force on the car.

We make a scale drawing of the forces as shown in Fig. 9.8(b), measuring the magnitudes of the forces with a ruler and the angles with a protractor. [The scale drawing of the forces is made larger and with a different scale than that in Fig. 9.8(a) in order to get better accuracy.] We then complete the parallelogram and draw in the diagonal that represents the resultant force. Finally, we find that the resultant force is about 800 N and that it acts at an angle of about 16° from the first force.

Lift = 840 lb Drag = 320 lb Fig. 9.10