P11: Pressure Flashcards
What is the equation for pressure?
Pressure = force/area
What is the equation for the pressure of a liquid?
Pressure = height x density x gravitational field strength
What are the units for density?
Kg/m^3
Describe how upthrust occurs
When an object is submerged in liquid, it experiences a greater pressure on the bottom of the surface than on the top. This creates a resultant force upwards, which is upthrust.
What happens to the atmosphere when altitude is increased?
It gets less dense
What happens to the number of air molecules above a surface as the height of the surface above ground level increases?
The number decreases
Describe the air when the height of a surface increases
There is less air above the surface than below it meaning, atmospheric pressure decreases as the height increases
What determines the pressure of an object in liquid?
The weight of the water above the object, the density of the liquid and the gravitational field strength
When would an object sink?
If it is more dense than the liquid
When would an object float?
If it is less dense than the liquid