Afreight train completes its journey of 150 miles 1 hour earlier if its original speed is increased by 5 miles/hour. give the original speed of the train. a. 20 miles/hour b. 25 miles/hour c. 30 miles/hour d. 35 miles/hour

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.