Which earthquake scale is based mostly on human opinion and perception of recent events? richter scale moment magnitude scale modified mercalli scale fujita scale saffir-simpson scale?

Which of the following elements is in the same period as phosphorus? a. carbon c. nitrogen b. magnesium d. oxygen select the best answer from the choices provided a b c d

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?