A source emits sound with a frequency of 860 Hz. It is moving at 20.0 m/s toward a stationary reflecting wall. If the speed of sound is 343 m/s, what frequency does an observer riding with the source hear

Explanation:

f = 860 Hz

velocity of  source, vs = 20 m/s

velocity of sound, v = 343 m/s

use the formula of doppler's effect

the frequency reflected from the wall is

f' = 812.62 Hz

Frequency heard by the observer

f'' = 862.93 Hz

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

e/c, where e is its total energy