Conservation of momentum

Isolated system

• when no net external force is applied to a system

  • when there is no net force acting on a system then the total momentum has to remain constant

  • when two or more objects in an _____ system interact, the total momentum of the entire system stays constant

when two or more objects in an isolated system interact, the total momentum of the entire system stays constant

Remember: when two or more objects in an isolated system interact, the total momentum of the entire system stays constant

when there is no net force acting on a system then the total momentum has to remain constant

Remember: when there is no net force acting on a system then the total momentum has to remain constant

the object with more mass will have a smaller / slower speed

Remember: the object with more mass will have a smaller / slower speed

slower velocity / speed

more mass means what for the velocity?

momentum is conserved in all collisions

Remember: momentum is conserved in all collisions

Inelastic Collisions

• Definition: two objects stick together and have the same velocity after the collision

when two objects stick together and have the same velocity after the collision

what are inelastic collisions?

Collisions in 2D

• Momentum of an isolated system is conserved in all directions 

• use subscripts to identify 

  • the object (object 1 or object 2)

  • initial or final values

  • components (x or y)

for collisions in 2D use subscripts to denote whether you’re talking about the momentum of object 1 or 2, the initial value or the final value, the x-component or the y-component 

Remember: for collisions in 2D use subscripts to denote whether you’re talking about the momentum of object 1 or 2, the initial value or the final value, the x-component or the y-component 

P₁,i,x + P₂,i,x = P₁,f,x + P₂,f,x

write the conservation of momentum equation in 2D for the x direction:

P₁,i,y + P₂,i,y = P₁,f,y + P₂,f,y

write the conservation of momentum equation in 2D for the y direction: