Impulse Momentum

momentum

p =m\*v (kg x m/s)

equal to the mass of the object times the object’s velocity; is a vector

impulse

J = F \* △t (N x s)

area under F/t graph

impulse-momentum theorem

only external impulse can change an object’s momentum; J = △p and F \* △t = pF-po

Fpeak

point of maximum compression

Favg

= 0.5Fmax

greatest impulse

object bounces back and hurts the most

system of interest; isolated

momentum is conserved in collisions, if and only if, ALL colliding objects are considered to be part of the ________________________ __(A+B)__ and system is ______________ (no external forces are present)

po=pf or △p =0

elastic collision

momentum is conserved; kinetic energy is conserved; objects bounce and there is no damage; examples: billiard balls, bumper cars (greater impulse leads to bounce)

inelastic collision

momentum is conserved; kinetic energy is not conserved; objects bounce, damage or not; examples: any soft ball, real cars

perfectly inelastic collision

momentum is conserved; kinetic energy is not conserved; objects stick, damage or not; examples: clay balls, railroad cars, real cars

equals

if Ko ____ Kf, then the collision was elastic

if po ____ pf, then the collision is possible

does not equal

if Ko ________ Kf, then the collision was inelastic

if po _________ pf, then the collision is not possible

sound energy

kinetic energy can be lost and transferred into __________ because it takes an enormous amount of energy to make sound

explosion

reverse collision

conserved

collision is only possible/elastic when momentum is _____________

compare magnitudes during a head-on collision

bug hits car windshield

FBC = FCB → N3L pair of forces

△tB = △tC → same event

JBC = JCB → J = Ft and N3L

△pB = △pC → J= △p theorem

△VB > △VC → Mc \*△vc = △pB = △pC =mb x △VB

ab > ac → definition: a =△V/t