Question

A container is filled to a depth of 20cm with water. on top of the water floats a 30.0 cm thick layer of oil with specific gravity of 0.700, what is the absolute pressure at the bottom?

Please help!

Answer 1

To find the absolute pressure at the bottom of the container, we can use the formula:

P_total = P_atm + ρ_water * g * h_water + ρ_oil * g * h_oil

First, we know that the atmospheric pressure (P_atm) is about 101325 Pa.

Next, we can find the densities of the water and oil. The density of water is about 1000 kg/m³. The oil has a specific gravity of 0.700, so its density can be found by multiplying the specific gravity with the density of water:

ρ_oil = 0.700 * ρ_water = 0.700 * 1000 kg/m³ = 700 kg/m³

Now, we can find the weight of the water and the oil. To do this, we will use the gravitational acceleration (g), which is approximately 9.8 m/s². The height of the water (h_water) is 20 cm (0.2 meters), and the height of the oil (h_oil) is 30 cm (0.3 meters):

P_water = ρ_water * g * h_water
P_water = 1000 kg/m³ * 9.8 m/s² * 0.2 m
P_water = 1960 Pa

P_oil = ρ_oil * g * h_oil
P_oil = 700 kg/m³ * 9.8 m/s² * 0.3 m
P_oil = 2058 Pa

Finally, we can find the total pressure at the bottom:

P_total = P_atm + P_water + P_oil
P_total = 101325 Pa + 1960 Pa + 2058 Pa
P_total ≈ 104343 Pa

So the absolute pressure at the bottom of the container is approximately 104343 Pa.