Transcript Air Pressure, Forces, and Motion

Air Pressure, Forces, and Motion
Meteorology 101
Dr. Robert M MacKay
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 resist 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
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)
Centrifugal force an (Apparent Force)
Coriolis Force (apparent force
due to Earth’s 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
Coriolis Force
Geostrophic Winds
Geostrophic Winds
Gradient Flow