Pressure Flashcards
What is the equation for pressure?
Force normal to a surface
Area of surface
Why does a gas in a box exert pressure on all walls of the box?
Its molecules bombard the walls
What is pressure measured in?
Pa
What is pressure?
The force acting on each square area
What angle is pressure at in a box filled with a gas?
Right angles to the walls
What happens to the pressure of a box when the gas inside gains more kinetic energy?
It increases
Is pressure related to temperature?
Yes
If a gas is in a box then the box is made smaller what happens?
Particles become closer together and collisions occur more frequently and the walls are hit more
Pressure increase
What does applying pressure do to a gas?
Makes it compress
What does reducing pressure on a gas do?
Makes it expand
What is space?
A vacuum
What is the pressure of particles high in the Earth’s atmosphere?
Low
What is the pressure of particles low in the Earth’s atmosphere?
High
Do liquids experience pressure?
Yes
Why do liquids experience pressure?
Because of the weight of the liquid above the object
At what angle does pressure occur to every surface?
Right angles
In greater depths of liquid, what is the pressure?
Greater
What is the formula for pressure due to a column of liquid?
Height of column x density of liquid x gravitational field strength
Describe the particles/pressure when temperature rises
- more kinetic energy
- higher speeds
- more collisions with more force
- more force = higher pressure
What is absolute 0?
- 273.14 degrees C
- 0K
What happens at absolute 0?
Particles are the coldest they can be
Particles have no kinetic energy
Only force acting upon them is gravity so rather than being suspended in midair they fall to the ground
What happens if you heat a can then place it in water?
- can expands due to increasing pressure of particles
- expanding gas leaves through the entrance so very few particles are inside can
- when placed in water entrance is sealed and particles cool rapidly
- cool gas exerts little pressure on inside of can
- pressure from outside is much higher therefore crushes the can
What is Boyle’s Law?
Pressure x Volume = Constant
What is the mass of a leaf?
How much material there is
What is the weight of a leaf?
The gravitational force acting upon the leaf
What is the equation for weight?
Mass x gravitational field strength
What is the equation for the pressure of a certain depth of liquid?
Pressure = height/depth x density x gravitational field strength
What is the gravitational field strength of the Earth?
10N/kg
What is Archimedes’ Principle?
The upthrust exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces
If the weight of an object is greater than the upthrust will it sink or float?
Sink
If the upthrust is greater than the weight of an object will it sink or float?
Float
If the upthrust equals the weight of an object will it sink or float?
Float (partly submerged)
Does an object experience more pressure on its upper or lower surface?
Lower surface
What is the equation for the pressure difference at two points in a liquid?
Depth difference of the two points x density of the liquid x gravitational field strength
