At a coal mine, a train engine bumps an empty hopper car that has a mass of 1 * 10^4 kg such that it rolls at a constant speed of 2 m/s under a coal storage bin. When the car triggers a switch on the track under the storage bin, the bin drops a load of 1.2*10^4 kg of coal into the hopper car. What is the speed of the cart after the additional coal?

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.