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.

they should be similar or the same

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.