1. ¿En qué casos la distancia tiene el mismo modulo que el desplazamiento?

                 spanish

El espacio recorrido o distancia recorrida se mide siempre sobre la trayectoria, a diferencia del desplazamiento, en el que sólo cuentan el punto inicial y final del movimiento. Cuando la trayectoria es una linea recta, el espacio recorrido es igual al módulo del desplazamiento.

                                           ENGLISH

The space traveled or distance traveled is always measured on the path, unlike the displacement, in which only the starting and ending points of the movement count. When the path is a straight line, the space traveled is equal to the modulus of the displacement.

world war i had a devastating effect on german-americans and their cultural heritage. up until that point   german-americans, as a group, had been spared much of the discrimination, abuse, rejection, collective mistrust experienced by so many different racial and ethnic groups in the history of the united states. indeed, over the years, they had been viewed as a well integrated and esteemed part of american society. all of this change with the outbreak of war.  

permafrost layer, it exists beneath a layer of soil, rock or sediment.