Canada geese migrate essentially along a north–south direction for well over a thousand kilometers in some cases, traveling at speeds up to about 100 km/h. If one goose is flying at 100 km/h relative to the air but a 40-km/h wind is blowing from west to east,
(a) at what angle relative to the north–south direction should this bird head to travel directly southward relative to the ground?
(b) How long will it take the goose to cover a ground distance of 500 km from north to south? (Even on cloudy nights, many birds can navigate by using the earth’s magnetic field to fix the north–south direction.)