Transcript Air Pressure, Forces, and Motion

Air Pressure, Forces, and Motion
Meteorology 101
Dr. Robert M MacKay
Pressure
density 
Mass

Volume
M
r
V
Temperature
Volume
The Gas Law
P=C*density*Temp
P=2.87 r T
Gas Laws
Gas Laws
Constant P as T increases V Increases/decreases
Constant V as T increases P Increases/decreases
Constant T as V increases P Increases/decreases
Constant V,T as M increases P Increases/decreases
Gas Laws
Constant P as T increases V Increases/decreases
Constant V as T increases P Increases/decreases
Constant T as V increases P Increases/decreases
Constant V,T as M increases P Increases/decreases
Mercury Barometer
Pressure Measurement
1013 mb = 1013 hPa
Millibar
hectoPascal
1013 mb
29.92 in Hg
76 cm Hg
760 mm Hg
760 Torr
14.7 psi
Station Pressure + Elevation(meter)/10
= Sea Level Pressure
Newton’s Laws of Motion
Newtons 3 laws of motion
1. Law of inertia
2. Net Force = mass x acceleration
(F=MA)
3. Action Reaction
1st Law (Law of Inertia)
Every object continues in its state of rest, or
of uniform motion in a straight line, unless
it is compelled to change that state by
forces impressed upon it.
acceleration = 0.0 unless the objected is
acted on by an unbalanced force
1st Law
Inertia (The intrinsic tendency of an object
to rest changes in motion)
Mass is a measure of an object’s inertia
Mass is also a measure of the amount of an
object’s matter content. (i.e. protons,
neutrons, and electrons)
Newton’s 2nd Law
• Net Force = Mass x Acceleration
•
F = MA
Newton’s Law of Action
Reaction (3rd Law)
• You can not touch without being touched
For every action force there is
and equal and oppositely directed reaction force
Forces that influence the wind
1. Pressure Gradient Force
2. Coriolis Force
4. Friction
On average gravity nearly balances the vertical Pressure gradient
(hydrostatic balance)
Pressure Gradient=∆P/dist
Pressure Gradient
Centrifugal force an (Apparent
Force)
Centrifugal force an (Apparent Force)
Coriolis Force (apparent force
due to Earth’s rotation)
Coriolis Force
Coriolis Force
Coriolis Force
Coriolis Force