When light from the sun strikes the surface of the earth, this light is absorbed by the ground. the ground, in turn, emits infrared light—which is actually invisible to human eyes—back into the air. what is the effect of this infrared light being released into the air from the ground? a. it makes the air brighter. b. it warms the air. c. it harms the ozone layer. d. it makes the air appear blue.

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.

You can watch static electricity in action by rubbing an inflated balloon against your hair. your hair will actually stand on its end! it does this because each hair becomes charged, and they all repel one another.

Use the illustration to describe how the electromagnetic spectrum changes as its frequency moves from radio waves to higher energy gamma waves in terms of wavelength and amplitude.