pressure
a force exerted over an area on the surface of an object
pressure and area
pressure decreases as the area over which a force is distributed increases
pressure equation
Pressure = Force over Area
force unit of measurement
Newtons (N)
area unit of measurement
square meters (m2)
pressure unit of measurement
pascal (Pa)
fluid
a material that can easily flow
What causes fluid pressure?
As each particle in a fluid collides with a surface, it exerts a force on the surface
air pressure
air has mass, gravity pulls down on this mass, this pulls creates weight which causes force or air pressure
balanced pressure
pressure is exerted equally in all directions
atmospheric pressure and elevation
as your elevation increases, atmospheric pressure decreases
water pressure and depth
water pressure increases as depth increases
barometer
instrument used to measure atmospheric pressure
What 2 factors does pressure depend on?
force and area
buoyant force
the upward force that water and other fluids exert
gravity and the buoyant force
buoyant force acts in the opposite direction of gravity, it makes objects feel lighter
Archimedes' Principle
the buoyant force on a submerged object is equal to the weight of the fluid displaced
density
the mass per unit volume of a substance
density equation
Density = Mass over Volume
How can you predict if an object will float or sink?
compare the density of the object with the density of the fluid
Pascal's Principle
force applied to a confined fluid will change pressure equally to all parts of the fluid
hydraulic devices
by changing the area, the force can be multiplied
hydraulic system
uses liquids to transmit pressure in a confined fluid
What are some uses of hydraulic systems?
lifts for heavy objects and breaks on a car
Bernoulli's Principle
the faster a fluid moves, the less pressure the fluid exerts
lift
an upward force
How does Bernoulli's Principle help explain flight?
air moves faster above the wing of the plane and causes lift
How does an atomizer work?
higher pressure at bottom of tube pushes perfume upward
What makes fluids flow?
fluids naturally flow from an area of high pressure to an area of low pressure