The gravitational force between which two objects would be the most difficult to notice?
OA. a water particle and an air particle
OB. the Moon and a water particle
C. the Earth and the Sun
OD. the Moon and the Earth

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

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.

A51 kg woman skis down a hill and her kinetic energy is 9.96e4 j. what is her speed?