Conservation of Momentum

The class began with the perpetual note-taking on the subject of Momentum; included in the aforementioned topic was the extended subtopic of the Conservation of Momentum. Various types of collision and explosion are included in the conservation of momentum—they are:

Explosion from Rest- One object splitting into multiple; given by the formula M1V1=-M2V2( and various manipulations of it).

Explosion from Motion-An object in motion, therefore with a initial velocity NOT of zero, splits into multiple objects; given by the formula (M1+M2)Vi=M1Vf1+M2Vf2

Elastic Collision-Two separate objects (with two separate masses and velocities) collide and rebound; given by the formula M1V1i+M2V2i=M1V1f+M2V2f

Inelastic Collision- Two objects colliding and becoming one; given by the formula M1V1i+M2V2i=(M1+M2)Vf

NOTE: All of these formulas can be derived remembering the Law of Conservation of Momentum, that is, initial momentum of an isolated system is equal to its final momentum, or the total momentum of an isolated system does not change.

Ex.)

A 95kg Unger collides while running 5.0m/s into a static Boss with a mass of 76kg. If Unger rebounds with a velocity of 3.0m/s, what is the velocity of the object he collided with?

M1V1i+M2V2i=M1V1f+M2V2f

M1=95kg

M2=76kg

V1i=5.0m/s

V2i=0.0m/s

V1f=3.0m/s

V2f=?

((95kg)(5m/s)-(95kg)(3.0m/s))/76kg=V2f=2.5m/s

We then continued with textbook questions on page 149, #1-5.

Whoever is left is next.