1. Momentum

2. Storm Damage  A house takes damage from the force of a 60 mph gale-force wind. If the house is subject to a hurricane at 120 mph the force on the house is A) Equal.A) Equal. B) Two times stronger.B) Two times stronger. C) Four times stronger.C) Four times stronger. D) Eight times stronger.D) Eight times stronger.

3. Linear Momentum  Momentum is the measure of inertia in motion. Momentum equals mass times velocityMomentum equals mass times velocity Momentum is symbolized by pMomentum is symbolized by p  Like velocity, momentum is a vector. Momentum is parallel to velocityMomentum is parallel to velocity m p v

4. Momentum and Force  The dimensions of momentum are ML/T.  The dimensions of force are ML/T 2.  Dimensional analysis: momentum is force times time. Force applied over time changes momentumForce applied over time changes momentum

5. Applying Action  The law of action uses mass and acceleration.  Acceleration is the time rate of change of velocity.  If the mass is constant the force depends on momentum.

6. Law of Action Redefined  Newton originally framed the second law (action) in terms of momentum, not velocity. The rate of change in momentum is proportional to the net force and the change is in the same direction as the forceThe rate of change in momentum is proportional to the net force and the change is in the same direction as the force Rocket: has momentum Force: changes momentum Initial momentum Final momentum: changed by the force

7. Storm Force  At 60 mph the momentum of the air is due to the mass (m) and velocity (v).  At 120 mph the speed is double. Half as much time to get the same amount of mass p = mvp = m(2v)

8. Bounce  A falling ball has a momentum.  After hitting the floor there has been a change in momentum.  The change is due to a force from the floor. next pipi pfpf FNFN