Ch. 7 Momentum

1. Linear Momentum

1.1. vector Quanity having same direction as the velocity

1.2. The vector of p = mass times the vector of velocity

1.3. The momentum and changes of two objects are always equal and opposite

2. Momentum

2.1. Vector quanity

2.2. For momentum to be Conserved these things must be constant

2.2.1. Magnitude

2.2.2. Direction

2.3. Mass and velocity involved

2.4. Conservation

2.4.1. If no external force acts on system, the initial momentum of the system is equal to the final momentum of the system.

3. Collisions

3.1. Completely Inelastic

3.1.1. “Perfect Sticking”

3.1.2. Conservation of only momentum

3.1.3. m1v1i +m2v2i = (m1 +m2 )vf

3.2. Inelastic

3.2.1. “Sticky” but the bodies do not stick together

3.2.2. Conservation of momentum only

3.3. Elastic

3.3.1. “Perfect bouncing”

3.3.2. Conservation of kinetic energy and momentum

3.3.3. m1v1i +m2v2i = m1v1f +m2v2f

4. System of Particles

4.1. Center of Mass

4.1.1. Average location of the mass in a system of particles

4.1.2. 3D in general

4.1.3. Motion of the Center of Mass

4.1.4. Isolated system moves at a constant velocity

5. Problem solving: Collisions

5.1. Draw before and after diagrams

5.2. Collect and organize data on masses and velocities

5.3. Set the sum of momenta of the two before the collision = to the sum of the momenta after the collision

5.4. Write one equation for each direction

5.5. If perfectly inelastic set final velocities equal

5.6. If perfectly elastic set final kinetic energy equal to initial kinetic energy

5.7. Solve for unknown quantities

6. Words of the Day

6.1. Transpicuous

6.2. Trust

6.3. Woolgathering

6.4. Applicability