A car is moving towards a stop sign at a speed of 25 m s−1. The driver applies the brakes 20 m before the sign and decelerates uniformly to rest just before the sign.

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.