If an aircraft is flying at 400 miles/hour and encounters a head wind of 40 miles/hour, what is the resultant ground speed?

Engines for propeller-driven aircraft are limited in their maximum rotational speed by the fact that the tip speed of the propeller must not approach the speed of sound in air (mach i). taking 6 ft as a typical diameter for a propeller of a light airplane and 1100 fils as the speed of sound, find the upper limit on the rpm (revolutions per minute) of the propeller shaft.

What difference are found in the propagation of sound in the media solid, liquid and gas

How do you find the density of a cork