un velero zarpa dispuesto a navegar 120 km al norte. una tormenta inesperada, empuja el barco a 100 km en una direccion de 30° al sur de este desde su punto de partida. ¿en que direccion debe arrancar de nuevo para llegar a su destino?

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.

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other

Iwould say the answer is d