Monday 1/11/21
No Google Classroom warmup!
finished worked M14 together
went over FR solutions to Mooney Review Packet
discussed center of mass (this time focus is on continuous mass distributions)
discussed several center of mass examples
introduced finding moment of inertia (rotational inertia)
discussed several moment of inertia examples
reviewed the difference between finding the center of mass and the rotational (or moment of) inertia
Tuesday 1/12/21
No Google Classroom warmup!
discussed center of mass (this time focus is on continuous mass distributions)
discussed several center of mass examples
introduced finding moment of inertia (rotational inertia)
discussed several moment of inertia examples
reviewed the difference between finding the center of mass and the rotational (or moment of) inertia
Wednesday 1/13/21
No Google Classroom warmup!
students worked on finding the center of mass for a collection of discrete mass points (several examples)
students worked on finding the rotational inertia about specific axes for a collection of discrete mass points (several examples)
worked out moments of inertia for stick (about end), stick (about middle), hoop, and disk.
discussed calculating the rotational energy of a stick whirled about its end; about its middle....given omega, the mass and the length of the stick
reminder: Google Classroom warmup Thursday and Friday
Help Video on Rotational Inertia (review video from APlusPhysics)
Screencastify introducing the rotational inertia quantity (my review video)
Thursday 1/14/21
Google Classroom warmup
reviewed working out moments of inertia for stick (about end), stick (about middle); discussed determining moments of inertia for hoop and disk about axes through their centers
rotational inertia of a solid cylinder...see this video for nice explanation!
found rotational inertia of a washer about axis through center
found rotational inertia of a hollow cylinder (inner radius a and outer radius b) about axis through center
Help Video on Rotational Inertia (review video from APlusPhysics)
Screencastify introducing the rotational inertia quantity (my review video)
Friday 1/15/21
Google Classroom warmup
reviewed working out moments of inertia for stick (about end), stick (about middle); discussed determining moments of inertia for hoop and disk about axes through their centers
rotational inertia of a solid cylinder...see this video for nice explanation!
discussed all formulae for typical rotational inertia
discussed parallel axis theorem
found rotational inertia of a washer about axis through center
found rotational inertia of a hollow cylinder (inner radius a and outer radius b) about axis through center
students spent any remaining time working on Mastering assignments
Help Video on Rotational Inertia (review video from APlusPhysics)
Screencastify introducing the rotational inertia quantity (my review video)
Tuesday 1/19/21
Google Classroom warmup
worked several more difficult problems requiring finding the rotational inertia
discussed several additional examples of calculating rotational inertia using the parallel axis theorem...gave some hints for Wednesday night's hw
discussed all linear/rotational analogies
defined torque...discussed how to calculate torque, discussed how to assign a direction to torque...great introductory video here
Wednesday 1/20/21
reviewed torque...discussed how to calculate torque, discussed how to assign a direction to torque...great introductory video here
discussed short cuts to finding torque (r perpendicular *F ; and F perpendicular*r)
Thursday 1/21/21
eLearning
Asynchronous eLearning Day directions: follow the itinerary below...
work M17 from the four M problems I gave you...also found here: M17 warmup; only work 15 minutes and then submit a picture/scan of this warmup to the Google Classroom assignment found in Unit 6: Rotational Mechanics
watch me discuss the metal plate net torque problem on video below
please complete torque worksheet...after completion, attach a pic/scan of your completed worksheet to the Google Classroom assignment mentioned above.
Today's Recording ... (about 17.5 minutes)
Friday 1/22/21
eLearning
Asynchronous eLearning Day directions: follow the itinerary below...
work M18 from the four M problems I gave you...also found here: M17 warmup; only work 15 minutes and then submit a picture/scan of this warmup to the Google Classroom assignment found in Unit 6: Rotational Mechanics
watch me discuss a situation in which a cord is wrapped around the rim of a wheel of known rotational inertia I...found the angular acceleration...had to use the relationships torque=(inertia)(alpha) and torque=(magnitude lever arm)(magnitude force)(sin of angle between lever arm direction and force direction). Also discussed how rotational kinematics stuff could then be determined once alpha is found. (video below)
watch me discuss a review problem about rotational kinematics (video below)
please work M19 (only work for 15 minutes please)...and then submit a picture/scan of this warmup to the Google Classroom assignment found in Unit 6: Rotational Mechanics
Today's Recording...about 20 minutes
Monday 1/25/21
livestream
students took Unit 6 Quiz
went over solutions to torque worksheet
discussed a 2nd review problem about rotational kinematics
solved the Atwood's Machine (massless pulley)...again.
Tuesday 1/26/21
students retake Unit 6 Quiz
analyzed Atwood's Machines with "massive pulleys...here is a video of an experiment using an Atwood's Machine at MIT
Wednesday 1/27/21
Google Classroom warmup while several are retaking Unit 4 Quiz 1 (Energy Conservation)
discussed Unit 4 MC Exam Solutions
continued analyzing Atwood's Machines with "massive pulleys...here is a video of an experiment using an Atwood's Machine at MIT
Today's Recording
Thursday 1/28/21
livestream
Review sites: Flipping Physics Mechanics Review Videos ; Sharpie Man Review Videos
students took midterm final
No Recording Today
Tuesday 2/2/21
discussed your Flipgrid assignment
continued analyzing Atwood's Machines with "massive pulleys...here is a video of an experiment using an Atwood's Machine at MIT;
revisited Atwood's Machine with a disk (found a, Tr, Tl);
visited Atwood's Machine with a hoop pulley (found a, Tr, and Tl)
worked a problem in which a "stone" (really a hanging mass) was released below a stationary pulley and accelerated downward. We found the linear acceleration, the tension, and the mass of the "stone". We were initially given linear motion information about the descent of the "stone". The concepts used were: CA motion analysis, torque=(I)(alpha), a=R(alpha), and Fnet=ma.
begin discussing rolling without slipping with notes
here is a movie explaining how an object rotates and translates at the same time
used the concept of rolling without slipping (along with conservation of energy) to determine the speed of different rolling shapes at the bottom of a ramp having been released from rest...found v_bot for hollow sphere, hoop, cylinder, and solid sphere.
Wednesday 2/3/21
continued analyzing Atwood's Machines with "massive pulleys...here is a video of an experiment using an Atwood's Machine at MIT; we checked the numbers!
begin discussing rolling without slipping with notes
here is a movie explaining how an object rotates and translates at the same time
used the concept of rolling without slipping (along with conservation of energy) to determine the speed of different rolling shapes at the bottom of a ramp having been released from rest...found v_bot for hollow sphere, hoop, cylinder, and solid sphere.
revisited pure rolling down a ramp this time analyzing the situation with forces and torques
Thursday 2/4/21
continued analyzing pure rolling down a ramp this time analyzing the situation with forces and torques...got a value for acceleration...checked it with what we would have gotten for acceleration from analyzing with conservation of energy and CA...got the same thing!
students worked on B problems for review work (while listening to smooth jazz). Here are problems B1-B16 and here are problems B17-B20
Friday 2/5/21
discussed some hw hints for Mastering assignment on torque
introduced angular momentum for a point mass; introduced angular momentum for an extended mass rotating about an axis
discussed how the angular momentum of an object moving in a straight line relative to a point not on that line is constant!
discussed an example involving angular momentum of a system of two point-mass particles moving in different directions relative to a designated origin
Monday 2/8/21
discussed another example of a point mass moving relative to a designated origin
discussed how conservation of angular momentum works with "collisions" of rotating objects
discussed examples requiring the use of conservation of angular momentum
Tuesday 2/9/21
discussed another example of a point mass moving relative to a designated origin
discussed how conservation of angular momentum works with "collisions" of rotating objects
discussed examples requiring the use of conservation of angular momentum
Wednesday 2/10/21
students worked on Pivot Interactives: Analyzing Rotational Motion using a Bicycle Drivetrain
students worked on Pivot Interactives: Rotational Collisions-Disk on Disk
students worked on Pivot Interactives: Wheels Accelerated by Hanging Weight (here is video hint to help you with this Pivot!)
students worked on Pivot Interactives: Ramp Rolling with Various Objects
Thursday 2/11/21
students worked on Pivot Interactives: Analyzing Rotational Motion using a Bicycle Drivetrain
students worked on Pivot Interactives: Rotational Collisions-Disk on Disk
students worked on Pivot Interactives: Wheels Accelerated by Hanging Weight (here is video hint to help you with this Pivot!)
students worked on Pivot Interactives: Ramp Rolling with Various Objects
when students completed Pivot Interactives, they worked on UT Quest Daily Assignments
Friday 2/12/21
students took Unit 6 Quiz 2
discussed appropriate units for rotational mechanics problems
discussed finding I of a pulley/mass system if one knows m of the mass, R of the pulley, and a of the mass
found the time for a spherical shell to reach the bottom of a ramp using both conservation of energy and torques/forces
figure everything out about a conical pendulum...given theta, m, g, and L....find v_t, a_radial, I, K_rot, K_trans, r, and omega
Monday 2/15/21
livestream
revisited the conical pendulum example from Friday...found a glaring error and so we will redo: figure everything out about a conical pendulum...given theta, m, g, and L....find v_t, a_radial, I, K_rot, K_trans, r, and omega
discussed a mixture of review problems involving conservation of energy, torque, CA, Fnet=ma, etc.
introduced static equilibrium with a Flipping Physics video
discussed leaning ladder problem (friction on floor...no friction on wall); this is the first static equilibrium problem requiring both net force equaling 0 and net torque equaling 0.
began discussing additional problems requiring application of static equilibrium
Tuesday 2/16/21
continued discussing additional problems requiring application of static equilibrium
continued discussing a mixture of review problems involving conservation of energy, torque, CA, Fnet=ma, etc.
discussed solutions to Unit 6 Quiz 2 and discussed revisions to the retake on Thursday.
students continued working on M20-M23
Wednesday 2/17/21
livestream
continued discussing a mixture of review problems involving conservation of energy, torque, CA, Fnet=ma, etc.
students continued working on M20-M23
handed out Mooney Review for Rotational Dynamics...students worked through all MC questions.
Thursday 2/18/21
livestream
students took Unit 6 Quiz 2 Retake
reviewed momentum/impulse and rotational mechanics
students continued working on M20-M23
handed out Mooney Review for Rotational Dynamics...students worked through all FR questions.
Friday 2/19/21
Sub Day: no livestream
students continued working on M20-M23 in the following order: 20, 22, 23, 21
students continued Mooney Review for Rotational Dynamics...students worked through remaining FR questions.
students should then work on the 2nd review packet (Princeton Review)
test moved to Wednesday so we can go over all of these FR Monday
Monday 2/22/21
livestream
discussed solutions to M20-M23 in the following order: 20, 22, 23, 21
discussed solutions to remaining FR problems Mooney Review for Rotational Dynamics
gave out answers to MC questions from 2nd review packet (Princeton Review)
test moved to Wednesday so we can go over all of these FR Monday
Tuesday 2/23/21
eLearning
no livestream
go to Google Classroom and complete eLearning Tuesday 2/23/21 activities.
No Recording
Wednesday 2/24/21
livestream
discussed falling freely (no air, called Free Fall) and falling in air
Mechanics Exam 5