Momentum Chapter 9

Impulse and Momentum

Applications  Science of Speed: Momentum Science of Speed: Momentum

Example Problem  9-4 A driver accelerates a 240 kg snowmobile, which results in a force being exerted that speeds up the snowmobile from 6 m/s to 28 m/s over a time interval of 60 s. b. What is the snowmobile’s change in momentum? What is the impulse on the snowmobile? c. What is the magnitude of the average force that is exerted on the snowmobile?

Angular Momentum

Conservation of Momentum  We saw that to change the momentum of an object we can exert an impulse on it.  The force or impulse must be exerted by an object outside the object.  So if no net force or net impulse acts on a system, the momentum of the system will not change.  This is the law of conservation of momentum.

Laws of Conservation of Momentum

Collisions

Example Collision Problem  During a goal-line stand, a 75-kg fullback moving eastward with a speed of 8 m/s collides head-on with a 100-kg lineman moving westward with a speed of 4 m/s. The two players collide and stick together, moving at the same velocity after the collision. Determine the post-collision velocity of the two players. Momentum Before CollisionMomentum After Collision Fullback Lineman Total

Example Problems  9-13 Two freight cars, each with a mass of 3 x 10 5 kg, collide and stick together. One was initially moving at 2.2 m/s and the other was at rest. What is their final speed?  9-14 A kg hockey puck moving at 24 m/s is caught and held by a 75-kg goalie at rest. With what speed does the goalie slide on the ice?  A disc with moment of inertia 1 kg·m 2 spins about an axle through its center of mass with angular velocity 10 radians/s. An identical disc which is not rotating is slid along the axle until it makes contact with the first disc. If the two discs stick together, what is their combined angular velocity?

Conservation of Angular Momentum  Angular Momentum Conservation Demo Angular Momentum Conservation Demo  Aerial Skiing Aerial Skiing  Cat Video Cat Video  Ice Skating Ice Skating  Circus Physics Circus Physics  Angular Momentum on the ISS Angular Momentum on the ISS

Linear Momentum Demonstrations  International Space Station International Space Station  Momentum in Football Momentum in Football  Circus Physics Circus Physics  Science of NFL Football Science of NFL Football

Lab Simulations  Collision Carts – complete worksheets for: Collision Carts  Elastic Collisions  Inelastic Collisions  Time permitting, try other simulations on this pagethis page