230 likes | 387 Views
Momentum. Momentum = inertia in motion. Moving object has large momentum if Mass is large ( ship moving at slow speed ) or Velocity is large ( bullet moving at rapid speed ) or Mass and Velocity are large ( massive truck rolling down a steep slope with no brakes ).
E N D
Momentum = inertia in motion Momentum
Moving object has large momentum if • Mass is large (ship moving at slow speed)or • Velocity is large (bullet moving at rapid speed)or • Mass and Velocity are large (massive truck rolling down a steep slope with no brakes) Momentum
What is the momentum of the truck if it is NOT moving? Momentum
Why are the engines of supertankers turned off when they are 25 km from port? Momentum
Changes in momentum may occur: • a change in the mass of an object • a change in velocity, • or both. Momentum
If momentum changes but mass doesn’t • velocity changes…..AND • acceleration occurs. • What produces an acceleration? • FORCE bigger Force bigger Δ in velocity bigger Δ in momentum Momentum
Collisions • Elastic: • colliding objects rebound without deformation or generation of heat • Colliding objects BOUNCE OFF OF EACH OTHER! • Inelastic • Colliding objects become distorted, generate heat, and possiblySTICK TOGETHER! Momentum
Elastic Collisions Moving ball (green) strikes ball at rest (yellow) Green ball stops, yellow ball moves away Head-on collision: Both balls bounce away Two balls moving in same direction collide Green moving faster than yellow Momentum transferred from green ball to yellow Now yellow ball moving faster Momentum
Inelastic Collisions Sticking together! Momentum
Inelastic Collisions Deformation……………. Momentum
You are hovering (REST) next to the space shuttle in earth-orbit • Your buddy of equal mass (moving at 4 m/s) (with respect to the ship) bumps into you. • If she holds onto you, how fast do the two of you move after the collision? • 2x mass in motion after collision ½ v • The 2 astronauts move together with a velocity of 2 m/s after the collision. Momentum
Conservation of Momentum momentum before collision = momentum after collisionm1v1 = m2v2 Momentum
Big fish………little fish…… Momentum
Big fish…..little fish (part 2) Momentum
Before collision, momentum of the loaded cart is 150 kg*cm/s momentum of the dropped brick is 0 kg*cm/s; total system momentum is 150 kg*cm/s. After the collision, momentum of the loaded cart is 90.0 kg*cm/s momentum of the dropped brick is 60.0 kg*cm/stotal system momentum is 150 kg*cm/s. The momentum lost by the loaded cart (60 kg*cm/s) is gained by the dropped brick. Momentum
Before collision, momentum of the cart is 60 kg*cm/s momentum of the dropped brick is 0 kg*cm/s total system momentum is 60 kg*cm/s. After the collision, momentum of the cart is 20.0 kg*cm/s momentum of the dropped brick is 40.0 kg*cm/stotal system momentum is 60 kg*cm/s. The momentum lost by the loaded cart (40 kg*cm/s) is gained by the dropped brick. Momentum
Before the collision, momentum of the car is 20 000 kg*m/s momentum of the truck is 0 kg*m/stotal system momentum is 20 000 kg*m/s. After the collision, momentum of the car is -10 000 kg*m/s momentum of the truck is +30 000 kg*m/stotal system momentum is 20 000 kg*m/s. The momentum lost by the car (30 000 kg*m/s) is gained by the truck. Momentum
Before the collision, momentum of the truck is 60 000 kg*m/s momentum of the car is 0 kg*m/stotal system momentum is 60 000 kg*m/s. After the collision, momentum of the truck is 30 000 kg*m/s momentum of the car is 30 000 kg*m/stotal system momentum is 60 000 kg*m/s. The momentum lost by the truck (30 000 kg*m/s) is gained by the car. Momentum
Before the collision, momentum of the car is +20 000 kg*m/s momentum of the truck is -60 000 kg*m/stotal system momentum is -40 000 kg*m/s. After the collision, momentum of the car is -10 000 kg*m/s momentum of the truck is -30 000 kg*m/stotal system momentum is -40 000 kg*m/s. The momentum change of the car (-30 000 kg*m/s) is equal in magnitude and opposite in direction to the momentum change of the truck (30 000 kg*m/s) . Momentum
Before the collision, momentum of the car is +20 000 kg*m/s momentum of the truck is -60 000 kg*m/stotal system momentum is -40 000 kg*m/s. After the collision, momentum of the car is -40 000 kg*m/s momentum of the truck is 0 kg*m/stotal system momentum is -40 000 kg*m/s. The momentum change of the car (-40 000 kg*m/s) is equal in magnitude and opposite in direction to the momentum change of the truck (40 000 kg*m/s) . Momentum
Sources • http://www.physicsplace.com • http://www.physicsclassroom.com/ Momentum