Answer:
Explanation:
To solve this problem we use the Hooke's Law:
(1)
F is the Force needed to expand or compress the spring by a distance Δx.
The spring stretches 0.2cm per Newton, in other words:
1N=k*0.2cm ⇒ k=1N/0.2cm=5N/cm
The force applied is due to the weight

We replace in (1):
We solve the equation for m:
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:
1788.402 MJ
Explanation:
Work done = Force (N) x distance (m)
First we have to convert distance into metres:
173.8 x 1000 = 173,800 m
Then plug these values into the equation above:
173,800 x 10290 = 1788402000 J
The reason it's Joules (the unit for energy) is because work done = energy transferred
Now we have to convert Joules into Mega Joules:
1 J = 1/1000000 MJ
1788402000 J = 1788402000/ 1000000 = 1788.402 MJ