Monday 11/23/20
livestream
students took Mechanics Exam 4
watch this video developing the concept of conservation of momentum
watch this video for homework showing how to use the mass-velocity block (momentum charts) to solve problems
work Unit 5H Momentum/Impulse Practice 1 . Complete for homework.
Today's Recording
Tuesday 11/24/20
livestream
went over Unit 5H Momentum/Impulse Practice 1 .
defined momentum as mass times velocity ( or p=mv ) ... p is the variable for momentum ... the units for momentum are kg-m/s
Overview discussion: definition of momentum, 3 1D equations for conservation of momentum (bouncy, sticky, explosion), and several examples using 1D equations.
emphasized that collisions are "inelastic" when kinetic energy is lost...which is pretty much always the case in collisions and explosions (exceptions being in particle physics collisions)
introduced concept of 2D conservation of momentum ... just do conservation of momentum in each direction independently; your final velocity components can then be used to determine the final velocity
discussed a bunch of 1D conservation of momentum problems
Wednesday11/25/20
livestream
discussed the momentum impulse relationship
discussed all calculus derivatives and integrals to date
discussed examples of calculating impulse due to constant forces and time dependent forces...note that the impulse is the area captured by the F vs. t graph. For constant forces, one can just find the area geometrically...for time-dependent forces, one must use the integral of the F(t) w.r.t. time over the time interval
Today's Recording (59 minutes)
Thursday 11/26/20
livestream
discussed types of collisions: inelastic (K_sys,i > K_sys,f); elastic (K_sys,i = K_sys,f); and superelastic (K_sys,i < K_sys,f)
demonstrated a 1D collision simulator
discussed solving elastic collisions in the lab frame with examples (the lab frame is how we have been solving momentum conservation examples...elastic collision solutions involve setting up two conservation equations: conservation of momentum and conservation of energy)
There are three example problems (with solutions given) at the end of the video. You should work through one of them to see that you can get to the correct answer.
Today's Recording (48 minutes)
Friday 11/27/20
livestream
watch this video first on the concept of center of mass (3:49)
next, watch this video on the concept of center of mass velocity (8:34)
next, watch this video on solving an inelastic collision in the center of mass frame (4:29)
next, watch this video on solving an elastic collision in the center of mass reference frame (7:01)
discussed solving elastic collisions in center of mass frame with examples (see Today's Recording after watching the above videos in order)
Today's Recording (46:50 ... watch this after watching the videos above)
Saturday 11/28/20
livestream
no new recordings today
work on QAPCB5 2021 which is due Sunday, 11/29 at 11:59pm (focus is on inelastic collisions and also explosions)
work on Mastering assignment (large) APCB 14 2021 due Tuesday, 12/1 at 11:59pm (focus is on elastic collisions and momentum-impulse relationship)
Sunday 11/29/20
livestream
no new recordings today
work on QAPCB5 2021 which is due tonight, 11/29 at 11:59pm (focus is on inelastic collisions and also explosions)
work on Mastering assignment (large) APCB 14 2021 due Tuesday, 12/1 at 11:59pm (focus is on elastic collisions and momentum-impulse relationship)
Monday 11/30/20
livestream
students should watch this Screencastify video on how to calculate the center of mass of a uniform 1-dimensional rod of length L and mass M
students should watch this Screencastify video using the result of the previous video to figure out some details using the center of mass concept
students should watch this Screencastify video of a problem in which conservation of energy, conservation of momentum, and center of mass frames are utilized
discussed the remaining slides from momentum/impulse notes
Today's Recording
Tuesday 12/1/20
livestream
students should watch this Screencastify video on how to calculate the center of mass of a uniform 1-dimensional rod of length L and mass M
students should watch this Screencastify video using the result of the previous video to figure out some details using the center of mass concept
students should watch this Screencastify video of a problem in which conservation of energy, conservation of momentum, and center of mass frames are utilized
discussed the remaining slides from momentum/impulse notes