An airplane pilot wishes to fly directly westward. According to the weather bureau, a wind of 75.0km/hour is blowing southward. The speed of the plane relative to the air (called the air speed) as measured by instruments aboard the plane is 310km/hour . In which direction should the pilot head? 1. The wind is blowing southward at 75.0km/hour . In what frame of reference is this speed measured?

a. The speed is measured relative to the plane.
b. The speed is measured relative to the air.
c. The speed is measured relative to the ground.

2. An airplane pilot wishes to fly directly westward. According to the weather bureau, a wind of 75.0km/hour is blowing southward. The speed of the plane relative to the air (called the air speed) as measured by instruments aboard the plane is 310km/hour . In which direction should the pilot head?

3. In this particular problem, you can compare the speed of the plane relative to the ground (the ground speed) to known quantities to evaluate the reasonableness of your answer. Find the ground speed of the plane, vP/G.