Air Pressure, Forces, and Motion Meteorology 101 Dr. Robert M MacKay

Newtons Laws of Motion Newtons 3 laws of motion 1. Law of inertia 2. Net Force = mass x acceleration ( F = M A ) 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 resist changes in motion) Mass is a measure of an objects inertia Mass is also a measure of the amount of an objects matter content. (i.e. protons, neutrons, and electrons)

Newtons 2nd Law Net Force = Mass x Acceleration F = M A

Newtons 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

Velocity : Designates speed (how fast) and direction Example: 50 mi/hr North Acceleration: How fast the velocity changes Example: zero to 60 in 6 seconds A=10 mi/hr/sec

Is it possible to accelerate while traveling at a constant speed?

Forces that influence the wind 1. Pressure Gradient Force 2. Coriolis Force 3. Friction On average Gravity nearly balances the vertical Pressure gradient (hydrostatic balance)

Fig. 8-16, p. 203

Pressure Gradient=P/dist

Pressure Gradient

Centrifugal force an (Apparent Force)

Coriolis Force (apparent force due to Earths rotation)

Coriolis Force Deflects air to right in NH & Left in SH Is always zero at the equator Increases with latitude Increases with wind speed Increases as planet rotation speed increase

Coriolis Force

Geostrophic Winds

Gradient Flow