Conservation of
Momentum
During an interaction of objects, total
momentum of the system is constant,
regardless of the forces
Total initial momentum = Total final
momentum
Consider 2 Objects, 1 & 2,
Work
Very different from everyday meaning!
Work displacement caused by a force
Only when forces are parallel to
displacement
Objects MUST be moved
Simplest terms:
W Fd
If a force is applied at a
Power
Power (P) rate at which energy is
transferred
Rate at which work is done
Differs from everyday meaning
Power = work / time
W
P
Alternate forms,
t
Fd
P
t
d
P F
t
P Fv
Units J/s = watt (W) me
Momentum & Impulse
Momentum () quantity of motion
o "inertia" in motion
o Vector
Direction = velocitys direction
o Product of mass and velocity
= mv
o Large momentum:
Big mass moving
(Ex. Train at
Conservation of Momentum
During an interaction of objects, total
momentum of the system is constant, regardless
of the forces
Total initial momentum = Total final
momentum
o Consider 2 Objects, 1 &
Collisions
Types:
1. Elastic
2. Inelastic
Elastic Collisions Objects collide &
bounce apart w/o deformation
i = f
m1v1i m2v2i m1v1 f m2v2 f
KE is conserved
KEi = KEf
2
2
2
2
1
1
1
1
m
v
m
v
m
v
m
v
2
Collisions
2 Types:
1. Inelastic
2. Elastic
Perfectly Inelastic Collisions Objects
collide, stick together, and move with
common velocity
o Final mass = combined mass
o Consider 2 cars, m1 and m2, c
Momentum & Impulse
Momentum () quantity of motion
"inertia" in motion
Vector
Product of mass and velocity
mv
Large momentum:
Big mass moving
(Ex. Train at any velocity)
Small mass moving very f