Problem 30.

The captain of a plane wishes to proceed due west. The cruising speed of the plane is 245 m/s relative to the air. A weather report indicates that a 38-m/s wind is blowing from the south to the north. In what direction, measured to due west, should the pilot head the plane relative to the air?

Solution:

This is problem on the relative motion. The velocity of a plane is the vector sum of the velocity of an air and the relative velocity of the plane (relative to the air) as shown in the figure.

We know that the direction of the final velocity of the plane is from east to west (as shown in the figure).

Then from the triangle based shown in the figure we can find angle . This angle characterizes the direction of the relative velocity of the plane.

Then