1. Linear Momentum
vector quantity that describes the tendency of an object to continue
moving at constant velocity
product of mass and velocity
denoted by the symbol ‘p’
p = mv
the SI unit for momentum is kg m/s

2. Impulse
vector quantity that describes the change in momentum due to the application of force in a period of time
product of force and time when the force is applied
expressed in N s
Impulse: FΔt = mΔv

3. Impulse is equal to the change in momentum.
For example there is a change in momentum from 2 kg m/s to 20 kg m/s.
Therefore the impulse is 18 kgm/s.
If the contact time is 0.1 s then the force applied is 180 N since the impulse is
Ft.

4. A loaded tractor –trailer with a total mass of 5
A loaded tractor –trailer with a total mass of 5.0 X 103 kg traveling at 20 km/h coasts into a loading dock, coming to a stop in 0.64 s.
a. What is the change in the momentum of the tractor-trailer?
b. What is the magnitude of the force exerted on the tractor-trailer by the dock?

5. Law of Conservation of Momentum
“The total linear momentum of the system is conserved if there is no external force acting on the system .”
total momentum = total momentum
before collision after collision
mA viA + mBviB = mAvfA + mBvfB

6. Three Types of Collision
Elastic Collision - KE is conserved
Inelastic Collision – KE is not conserved and usually lost to heat and sound
Perfectly Inelastic Collision – objects stick together after the collision and KE loss is maximum