Momentum and collisions Flashcards
Motion map
A series of arrow-drawings that display the magnitude of the velocity vector at given time intervals to illustrate overall acceleration
Momentum of a single particle
Product of mass and constant velocity
p=m*v
Momentum in a multi-particle system
Sum of each particular momentum
Σp=m1v1+m2v2+…ect
Total momentum
Sum of all the objects’ momenta within a system
Σp=p1+p2
Change in momentum
Δp=FΔt=∫F(t)dt
Area under the force curve in the given time period
Impulse
Net change in momentum
I=Δp=FΔt=∫F(t)dt
Area under the force curve in the given time period
Law of conservation of momentum
In a closed system, the amount of momentum within the system remains constant
Units of momentum
Newton-seconds (Ns)
Calculating shifts in velocity based on impact
m1vi1+m2vi2=m1vf1+m2vf2
Use algebra from here
Equal mass collisions with a stationary object
All the momentum will be transfered,
The stationary object will carry with it the velocity vector, both magnitude and direction
Elastic collisions
The two objects bounce off one another and momentum is transfered
Inelastic collisions
Two objects stick together and their total mass reduces the final velocity
Measuring elasticity of a collision (with constant acceleration and a stationary object)
Coefficient of restitution
Cr=√(bounce height/drop height)
Or for horizontal systems
Cr=√(final distance from impact/starting dfi)
Describing vectors in momentum
p=(pi,pj,pk)
Converting velocity vectors to momentum vectors
Multiply each i j k component by object mass