Collisions Post-Lab
  kgm 
Pi 

s

The Law of Conservation of Momentum
In any closed, isolated system the total
momentum remains constant

Pf
  
Pi  P1fPf
 kgm 
s

Slope
Since the graph is linear
and contains (0,0)
 
Pi  Pf
Proof


FBR   FRB


p
Fnet 
t
Newton’s
Third Law!
tBR  t RB


FBR t   FRB t


J BR   J RB


pR  pB

Ptotal  0
OR
Newton’s
Second Law!
However, for an isolated
system, the only forces acting
are internal forces between
the object.
Since Newton’s Third Law
guarantees that those internal
forces always occur in equal
and opposite pairs, the net
force is zero!

p
0
t

P  constant