A teacher tells his class that a train is moving at 40 miles per hour. Does this tell them the speed of the train, the velocity of the train, or both?

Jet streams are relatively narrow bands of strong wind in the upper levels of the atmosphere. the winds blow from west to east in jet streams but the flow often shifts to the north and south. jet streams follow the boundaries between hot and cold air. the earth's rotation is responsible for the jet stream as well.