You are driving your car East at a speed of 30 m/s on a road along rail tracks. A train is moving West toward you at a speed of 10 m/s. The train blows its horn producing sound of frequency of 600 Hz. (vair = 343 m/s)
What frequency of the horn do you hear in [Hz]?
Suppose you pass the locomotive while the horn is still blowing. What frequency in [Hz] do you hear then?

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.