Question

identify the coordinate system you could use to describe the motion of a girl swimming across a rectangulral pool

Answer 1

Rectangular coordinate system - assuming a standard sized competitive swimming pool based on a "plan view" of pool with right hand corner of 'starting end' of pool as the origin. If a 'meter' pool use distance in meters, and if a 'yard pool' use distances in yards or feet. X-axis coordinates measured across width of pool; Y-axis coordinates measured along length of pool.
Consider swimmer to be a point. Initial swimmer location at x1,y1. After a short time interval = t, swimmer's new location is at x2,y2. If x2 - x1 < 1 unit of distance, then swimmer's avg speed = (y2 - y1)/t

Answer 2

Rectangular coordinates system

Step-by-step explanation:

in fact you could use any system but is easier to use the rectangular system because the pool (ussually) is a rectangle, so to use this system first you have to select a origin, if we look the pool from a top view the easiest way is to pick the bottom left cornet as the origin and from there meassure distances as in a coordinated plane, it means if the girl is somewhere in the pool we can tell her position meassuring the horizontal distance to her and then the vertical distance, that means that the position of the girl will look like this (x,y) and if she is moving, x and y will be varying during time like (x(t),y(t)).