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Newton's Laws

1. Law of Inertia A body naturally moves in a straight line 
at constant speed natural means no external influence on body
Sum Forces ON body = 0
2. Law of Non-Inertia. The net force ON a body causes an acceleration
in direction of net force and of magnitude given by
Sum of Forces ON body equals mass x acceleration.

3. Law of Action - Reaction.  ALL Forces are interactions 
between two bodies (A & B) If body A exerts force on body 
B (FAB), then body B exerts a force on body A (FBA) which 
is equal and opposite. FBA = - FAB
Other examples:
Conical Pendulum

Newton's Law for rotation
Toronado Bottle
Now on to Horse and Wagon

Apply 2nd Law to Wagon (4 wheels)

Path: FHW - 4 fSW = Mw apath
Perp: 4 FSW - FEW = Mw aperp

Apply 2nd Law to Horse (4 feet)

Path: 4 fSH - FWH = Mh apath
Perp: 4 FSH - FEH = Mh aperp
Other applications
Car Moving to Right

Car Coming At You and curving to right (your left)
Level Road ..................Banked Road

Now a little quiz about Newton's Laws
Concept of Collisions.......Explosions.

Application of Newton's 2nd and 3rd Laws.
F = m a  or  F = D(mv)/Dt
Or  F Dt = D(mv)
Where D = delta (change)
 mv = momentum

so force equals the rate of change of momentum of a body OR
Force acting for a time (Dt) causes a change in momentum.

For example, billiards

A: Head On Collision
B. Glancing Blow
Other examples:
Shooting guns

Shooting rockets

Interactive Physics