What is specific gravity

Apositive point charge q is fixed on a very large horizontal frictionless tabletop. a second positive point charge q is released from rest near the stationary charge and is free to move. which statement best describes the motion of q after it is released? assume q stays on the table

By what primary heat transfer mechanism does the sun warm the earth?

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.