Fluid: a substance that has definite mass but not definite shape. Ex: gases and liquids Density: mass/volume
ρ Units: ρ water = 1 g / cm3 =
__________kg/m2 = __________Kg/L
Weight of a Fluid – force gravity exerts on a fluid = mg Equation:
Specific Gravity - density of a fluid compared to the density of water. Specific Gravity - comparison of the density of a substance with the density of water
Alcohol or lead, which has a specific gravity of 11?
Pressure = F/A
N/m2 or Pascal
Pressure under a Liquid
P0 –
pressure above liquid
(Density in liq. depends only on h)
(Density depends only on h)
P0
– pressure above liquid
at sea level 1 atm = 1.013 x 105 N/m2
Pascal’s Principle If a force is applied on one place in an enclosed liquid the pressure
increases everywhere else in the liquid.
Giancoli p. 281) 14, 16 density of water = 1000 kg/m3
Buoyancy "Archimedes Principle"
Why do some substances float in a liquid and some sink?
Objects that are less dense than the liquid sink.
The buoyancy force produced by a liquid is equal to the weight of the volume displaced
FB= Weight of fluid displaced= Weight of fluid displaced FB = mg
Buoyancy force = submerged weight
(rfluid)(Vsubmerged)g
(rfluid)(Vsubmerged)
Gauge Pressure - fluid pressure w/o atmospheric pressure Absolute Pressure - fluid pressure with atmospheric pressure
Apparent Mass or Weight - mass or weight in fluid
V of liquid displaced = V of object submerged
Density / Part Submerged
Partially Submerged /
©Tony Mangiacapre., St. Mary's H.S., Manhasset,
NY |
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