Pressure In Fluid Flashcards
Formula for pressure
Force/area
How does pressure depend on the direction and the depth
-pressure in a liquid acts equally in all directions, at the same depth
Formula for force in fluids
Force = density x area x height x gravitational field strength
Formula for the difference in pressure
Density x gravitational field strength x difference in height
How to convert Kelvin to Celsius
0 KELVIN = -273 Celsius
Definition of kelvin
The average KE of the particles in a material so that 0 K is the point at which there is (theoretically) zero KE in the system (not actually possible)
Graph of temperature in kelvin against pressure
It will be directly proportional, as the temperature of a gas in kelvin is proportional to the average energy in the kinetic energy stores of its particles
Relationship between pressure 1, temperature 1 and pressure 2, temperature 2
P1/T1 = P2/T2
Relationship between pressure and volume
Pressure is inversely proportional to volume
What causes pressure
Colliding gas particles creates pressure
Waht does the equation pV give
A constant
Why does a lower temperature cause a lower pressure
-as the temperature decreases, the kinetic energy stores of the particles decrease as temperature is proportional to kinetic energy
-the average speed of the particles decrease
-the particles travel slower, and hit the walls with less force and less often, causing the outward force acting on the object to decrease
-the area of the object stays the same but the net force decreases, so the pressure decreases
How does less particles cause lower pressure
-the outward force acting on the object is equal to the sum of the forces exerted by all the particles in the object on its walls
-the outward gas pressure is equal to the net force acting per unit area on the object’s walls
-when the gas particle in the object decreases, collisions between the gas particles will occur less often, so the net force and pressure will also decrease
Why does the volume of a bubble increase as it rises when it is underwater
-as the bubble rises, the pressure of the water decreases, causing the pressure of the air inside the bubble to be greater than the pressure of the water acting on the bubble
-the volume of the bubble increases until the pressure of air inside the bubble becomes equal to the pressure of the water, therefore the bubble becomes bigger as it rises
Why is the pressure of water greater than the pressure of oil when the height is the same
-water has a higher density than oil
-density is directly proportional to pressure
-therefore the pressure is greater
