Apiece of spacecraft debris initially at rest falls to the earth's surface from a height above the earth equal to one-half of the earth's radius. find the speed at which the piece of debris hits the surface. neglect air resistance and the gravitational pull of the moon. express your answer with the appropriate units.

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?