forces - pressure in fluids Flashcards
what force are particles in a liquid/gas exerting?
force at right angles to the walls of the container
what are called fluids?
gases and liquids
pressure equation (Pa - pascal)
force normal to a surface (N) / area of that surface (m squared)
why do crisps packets swell up in aeroplanes?
when aeroplanes are flying, the air pressure in the cabin is kept at a slightly lower level than the air pressure on the ground. this means air pressure in bag is greater than in cabin causing it to inflate
what is the atmosphere?
a thin layer of air around the earth
where is atmosphere most dense?
at the surface of the earth. there is the greatest number of air molecules in a given volume
the atmosphere gets less dense as we
increase in altitude (move away from the surface of the earth)
what is the pressure of the atmosphere caused by?
air molecules colliding with a surface
what happens to the number of air molecules as surface increases height about ground level? what does this mean?
number of air molecules about the surface decreases . this means atmospheric pressure decreases with an increase in height
why do mountain climbers take oxygen tanks?
because air pressure may be too low to supply all the oxygen they need
