Momentum

1
Momentum

• inertia in motion

2
Momentum

• Car and Truck have same speed
• Two cars with different speeds
• More inertia ? Harder to stop
• Going faster ? Harder to stop
• Momentum is like Inertia in Motion
• Momentum mass x velocity

3
Impulse

• When you apply a force on an object, you change
  its momentum
• A force applied for a length of time is called an
  Impulse force x time
• This impulse equals the change in momentum so
• Ft change in mv ?mv

4
Wham! Bang! Bam! Kapow!

• Change in momentum depends on
• Strength of the Force
• Time of the Impact (how long the force is
  applied)
• EXAMPLES

5
Wabbit Hunting

• Firing a gun
• Which of Newtons Laws
• The bullets goes forward, the gun is pushed back
• Momentum before?
• After?

6
Conservation of Momentum

• The momentum of a system remains unchanged
  (unless there is an external force)

7
Collisions

• Conservation Law still applies
• Sum of Momentum Before Sum of Momentum After
• Types of Collision
• Objects bounce apart, no change in shape
  Elastic
• Objects are mishapen, heat exchanged (extreme
  case stick together) Inelastic

8
Collisions

• Pool balls bounce off each other
• Bouncy Ball hits the floor
• Car crash
• Ball of Clay thrown at the Wall

9
Homework

• Due Wednesday July 12
• Ch. 3
• Exercises 4,7,11,15,17,21,31,37,40
• Problems 1,3