[SOLVED] Airplane propeller and plane's velocity relative to the ground. 1. The problem statement, all variables and given/known data An airplane propeller rotates at 2200 rev/min while the airplane flies at a speed of 550 km/h relative to the ground. The plane's velocity is parallel to the propeller's axis of rotation. Part a) What is the speed of a point on the tip of the propeller, at radius 1.5 m, as seen by the pilot? Part b) What is the speed of a point on the tip of the propeller, at radius 1.5 m, as seen by an observer on the ground? 2. Relevant equations v=w times r v=w times r times sin delta 3. The attempt at a solution I got part a asking speed relative to pilot by converting 2200rev/min to m/s, but part b has me stuck...I don't know if I am missing an equation that I could possibly use but I tried to convert the speed relative to ground to m/s and add it to the 345.57m/s I got as the answer for part a.