Density and Pressure: Answers
State the equation linking pressure, force and area.
Pressure = force / area.
Calculate the pressure exerted on a 5 meter trampoline when a man weighing 750 Newtons jumps up and down.
Let’s assumed the trampoline is a square shape rather than a circular trampoline. The total area is 5 squared = 25 m2.
Pressure = force / area. Pressure = 750 / 25 = 30 N/m2.
Why is water at the bottom of the ocean more dense than water in shallow regions?
The water molecules at greater depths have the added pressure of the particles above them, increasing the pressure of the water and making it more dense.
State the equation linking pressure difference, height, density and g.
Pressure difference = height x density x g
Calculate the pressure difference for a manometer containing liquid with a density of 1260 kg/m3 and with a height of 0.25 m. Give the units.
To answer this question you need to know that the gravitational field strength on Earth is 10 N/kg.
Pressure difference = 0.25 x 1260 x 10 = 3150 Pa