Pressure Flashcards
how do molecules move in a gas
molecules of gas are in constant random motion
what is temperature of gas dependent on
amount of energy in kinetic stores of its molecules
what happens when you increase temperature of gas in a fixed volume
- pressure increases
- molecules move faster so more collisions
- collision means a change in momentum which exerts force on wall of container
how do we calculate pressure of gas at constant temperature
pressure x volume = constant temperature
what happens when work is done on a gas
- transfers energy to the gas
- increases internal energy of gas
- increase its temperature
how does pump increase pressure inside a bike tyre
- work is done to overcome pressure already in tyre to push in more molecules
- increases internal energy of air inside the tyre
- increases temperature
what is a fluid
a liquid or gas - anything that can flow
how is pressure caused in fluids
force applied normally to a surface
what is pressure like along horizontal line in fluids
pressure is the same at all horizontal points within the same fluid
how does hydraulic system transfer a force
- pressure in incompressible liquid is constant throughout
- force applied at one end of the pipe is transferred to the other end
- varying sizes of input and output pistons allows the force to be multiplied
how does upthrust work in a fluid
partially or fully submerged objects experience greater pressure on the bottom surface than on the top surface - creates a resultant upwards force called upthrust
how would we determine upthrust on an object
use the pressure difference between bottom and top of object using pressure equation to calculate upthrust
why would object float in a fluid
if the weight is less than the weight of the volume it displaces
what happens to density of atmosphere with altitude
gets less dense with increasing altitude
what is atmospheric pressure at sea level
100 kPa
