4. a person can swim 0.65 m/s in still water. she heads directly south across a river 130 m wide and lands at a point 88 m [w] downstream. k/u t/i a (a) determine the velocity of the water relative to the ground. (b) determine the swimmer’s velocity relative to earth. (c) determine the direction she should swim to land at a point directly south of the starting point.

speed of the person in still water = 0.65 m/s

width of the river = 130 m

distance covered downstream = 88 m

a) let the speed of the water be  = s

The time to cover two displacements would be equal.

b) Swimmer's velocity  relative to earth would be:

c) The swimmer should swim south of East to land at a point directly south of the starting point.

layers of the earth affect the waves and these effects are seen on instruiments such as seimometers