Because the top layer of a pool will be warmer than the bottom layer, that why filtration is important to cycle the water evenly.
Answer:
1) 
2) 
3) 

Explanation:
Given:
width of river, 
speed of stream with respect to the ground, 
speed of the swimmer with respect to water, 
<u>Now the resultant of the two velocities perpendicular to each other:</u>



<u>Now the angle of the resultant velocity form the vertical:</u>



- Now the distance swam by the swimmer in this direction be d.
so,



Now the distance swept downward:



2)
On swimming 37° upstream:
<u>The velocity component of stream cancelled by the swimmer:</u>



<u>Now the net effective speed of stream sweeping the swimmer:</u>



<u>The component of swimmer's velocity heading directly towards the opposite bank:</u>



<u>Now the angle of the resultant velocity of the swimmer from the normal to the stream</u>:



- Now let the distance swam in this direction be d'.



<u>Now the distance swept downstream:</u>



3)
Time taken in crossing the rive in case 1:



Time taken in crossing the rive in case 2:



Obesity is primarily caused by a lack of physical activity or by unhealthy dietary habits. The positive energy balance underlying obesity is generally attributed to chronic excess energy intake or reduced physical activity.
Based on what we know, we can confirm that the wave behavior being observed when light passes through media of different densities is refraction.
<h3>What is refraction?</h3>
This is a term used to explain the behavior of light as it moves through distinct mediums. This behavior includes a change in direction of the light due to its change in speed.
Therefore, the wave behavior being observed when light passes through media of different densities is refraction.
To learn more about light waves visit:
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