What percentage of the solar radiation entering the atmosphere is absorbed by the earth’s surface

20%
19%
51%

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.

Estimate the magnitude of the electric field due to the proton in a hydrogen atom at a distance of 5.29×10 to the power of −11 m, the expected position of the electron in the atom.

Abook is sitting on a table, completely still. what would happen if gravity suddenly stopped affecting the book? a. the book would move upward. b. the book would stay where it is. c. the book would fall. d. the book would move sideways.