The rock has potential energy due to the gravitational potential with the Earth. As the rock is falling, this gravitational energy becomes less. What happens to that energy? Question 11 options: The energy disappears. The energy is transformed into kinetic energy. The energy is absorbed by the ground and the air The energy is transformed into chemical potential energy.

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.