What is....??

Question

Determine the following or give the meaning of total force and the absolute pressure of the bottom of a swimming pool?

Answer 1

You need to remember that the pressure at the top is not zero, but atmospheric. So add that to the pressure at the bottom of the pool and you will have the absolute pressure.

Answer 2

Total force is the Mass (kg) of water acting on the Area (m²) of the pool bottom.
Area of pool bottom (m²) x height of water (m) x 1,000kg/m³ x 9.81m/s² = Total force of the water in Newtons).

Absolute pressure at the bottom is the pressure exerted by the water plus the atmospheric pressure.
1 metre height of water exerts a pressure of 0.1 atm.
The Absolute pressure therefore is found by...
(Depth (m) x 0.1atm/m) + 1 atm.
(This times 101.3kPa will give the pressure in Pascals.
or, multiply by 760 will give mmHg).

(P.S. The above answers are related to pure water. However, the Density difference is very small and won't change the overall figures by much).

Answer 3

Look at the bottom of the swimming pool, there is a pressure acting on you . which can be calculated as follows:=
Pressure = Density X Gravity acceleration X Height(Depth) .

Now total force = Weight - Upthrust Force .

Upthrust force is due to difference in pressure at the to than at the bottom .
Like for example :=
If you immerse a can of height h in water .
Upthrust equals:-

Pressure at bottom of can = Density X gravity acc. X Depth
Pressure at top = Density X gravity acc X(depth-h).
Density X gravity acc. X Depth - Density X gravity acc X(depth-h).
= Density X Gravity acceleration X (h) .
Pressure = force X area .
so Upthrust = Density X Gravity acceleration X (h) X area .
which can be simplified to
Upthrust = mass X Gravity acceleration .=Weight of the water displaced