The wavelength of light visible to the human eye is on the order of 4 x 10-7 m.
Find the frequency of the lightwave if the
speed of light in air is 2.99792 x 108 m/s.
Answer in units of s-1.

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of