P11 - Pressure and Surfaces Flashcards
What is meant by a force?
A push or pull
What is the definition for pressure?
Pressure is the force per unit area
What is the equation for pressure?
Pressure = force (N) / Area(m^2)
How do you calculate pressure due to liquids?
Pressure(Pascals-Pa) = height(m) x density(kg/m^3k) x gravity (N/kg or m/s^2)
What is the air pressure caused by?
Air pressure is caused by the force of air molecules bumping into things.
What is upthrust?
Upthrust is the upward force that a fluid (liquid or gas) exerts on a body (or object) floating in it.
What is archimedes’ principle?
An object totally or partially immersed in a fluid is subject to an upward force equal in magnitude (size) to the weight of fluid it displaces.
When does an object float?
An object floats when its weight is equal to the upthrust provided by the fluid.
When does an object sink?
An object sinks when its weight is greater than the upthrust provided by the fluid.
Explain how atmospheric pressure changes with elevation above sea-level.
As the elevation above sea level increases the atmospheric pressure decreases this means that they are in an inversely proportional relationship.
