P11 Force and pressure (paper 2) Flashcards
what is meant by the term ‘pressure’
the force per unit area
state Boyle’s Law
volume is inversely proportional to pressure (as volume goes up, pressure decreases)
what is the equation for pressure
pressure x volume = constant
pressure = force / area
pressure = density x gravity x depth
what is the unit for pressure
Pascals (Pa)
where is there more pressure in air (at the top or bottom)
bottom
why is there more atmospheric pressure at the bottom
because as you move away from the surface there are fewer particles of gas so the force they exert decreases with increasing altitude, less force exerted = less pressure
convert 1cm^2 to m^2
1x10^-4
when do gases exert a pressure
since the particles collide with surfaces and exerting a force
in a liquid, is there more pressure at the top or bottom
at the bottom (where it is deeper)
what is meant by the term ‘upthrust’
it is the upwards force due to a fluid
what is upthrust caused by
the pressure of the fluid, which is greater on the bottom of the object than the forcce applied by the object itself
what direction does pressure act in
all directions
when does an object float
when its weight is equal to the upthrust
when does an object sink
when its weight is greater than the upthrust
describe the relationship between altitude and atmospheric pressure
inversely proportional (as altitude increases, atmospheric pressure decreases)
if the liquid is very dense what is the pressure of the liquid like
very high too
what is atmospheric pressure at sea level
100kPa
why does water level of water rise when an object is lowered into the water
the object displaces some of the water
what is meant by the term ‘atmospheric pressure’
it is the pressure exerted by the air above us up to a height of many km. it can be thought of a a single layer of gas of constant density
state archemedies principle
the volume of the water displaced is equal to the volume of the floating object
is oil more or less dense than water
less dense than water (it floats on water)
if someone is wearing a heel do they create more or less pressure than someone wearing flats
more pressure
