AT Cycle 10

11/2 - 11/9

T 11/2

W 11/3

M 11/8

T 11/9

🔴 1: T 11/2, 🟡 3: T 11/2 - moment of inertia problems (virtual)

We will be all virtual today. Please use the Zoom link which can be found in Google Classroom at the bottom of your Classwork section.

Today, we'll work on problems from Chapter 10 on calculating moment of inertia:

Support: 42
Required: 36, 38, 40, 43, G50, G42, G46
Enrichment: G49, G51

While you do these problems, write at least one piece of advice on a sticky note on the class Jamboard (linked in Google Classroom). Make sure you put your name at the top of the note.

Homework: Watch the following video by Dan Fullerton on Rotational Dynamics. Watch ONLY from 6:06 to 19:30! Take your time working through these examples to really understand them. It would be a good idea to have these examples written down in your notes.

🟥 1: M 11/8 lab, 🟨 3: W 11/3 lab - torque of friction lab

Today, we'll start with a brief check-in of rotational dynamics which you should have learned about in the video last night.

Then, we'll investigate rotational dynamics more by looking at a particular torque - that of friction.

Is frictional torque a good thing or a bad thing? Check out this video of a bow drill fire "engineer."

Sometimes, it's important to know exactly how much frictional torque there is in a system. We'll do a lab where we try to calculate the torque of friction on the aluminum disk mounted on the wall. This activity will require you to put together all of the pieces of rotational dynamics that we've been working with in the past couple weeks. The lab write-up is in ↩️ Pivot Interactives "Finding the Torque of Friction (in-person)," although most of the lab will be done in person with the use of physical measurements and 🎞️ Vernier Video Analysis. (If you are absent for this lab, you may do ↩️ Pivot Interactives "Finding the Torque of Friction (virtual)" which does not require physical in-person measurements but rather requires you to make measurements from a video.)

Learning Goals of Massive Pulley Lab:

  • Be able to draw a free body diagram of a complex system, and use it to solve Newton's Law problem.

  • Be able to determine the moment of inertia of a physical pulley with the use of density.

  • Be able to utilize available technology to determine the type of motion of an object.

  • Be able to calculate the torque of friction on a rotating body.

  • Be able to link the torque of friction to a real-life application, and learn about engineering solutions, evaluating cost-benefit.

Massive Pulley Lab Requirements:

  • Large diagram of set-up with labeled measured distances

  • Free body diagrams of pulley and falling mass (make sure ALL forces are represented, remember that normal force and force of friction are components of the same force of contact)

  • Calculations to find the moment of inertia of the rotating massive pulley

  • Calculations to find the torque of friction (kinetic)

  • Explain why the torque of friction is easier to find than the force of friction (or what we would need to measure in order to find the force of friction)

  • Research on real-life applications and engineering solutions.

Safety considerations with the massive pulley lab:

Follow all directions in the lab. The Vernier caliper we'll be using has somewhat sharp edges, so be careful not to put it near anyone's eye or poke anyone's skin. In order to make measurements, you might have to be taller. Perhaps ask a taller student to collect measurements for your group or use the stepstool provided. Do not use a chair or lab stool to stand on. If you use the stepstool, have one other student assist you getting on and off. They should also stand nearby spotting you to make sure you don't fall. Don't do anything you're uncomfortable doing; call the teacher for assistance.

Homework: Finish the lab in ↩️ Pivot Interactives by Wednesday, November 10th at 10pm. Quiz on center of mass, moment of inertia, rotational kinematics, and tipping - Wednesday, November 10th. Lab quiz on Massive Pulley Lab on Friday, November 12th.

❤️ 1: T 11/9, 💛 3: M 11/8 - ✏️ massive pulley problems (1)

If anyone has not finished the lab, we'll finish that up today.

Today, we'll learn how to solve "massive pulley problems". We'll do these problems from Chapter 10:

Support: 49, 50
R
equired: 51, 53, 54, 55, 56, 69, 71, 98
Enrichment: 57, 87

We'll continue working on these problems next hour after the quiz.

Homework: Finish the lab by Wednesday, November 10th at 10pm in ↩️ Pivot Interactives. These massive pulley problems are due Friday, November 12th at 10pm to ✏️ Google Classroom. Study for Quiz on center of mass, moment of inertia, rotational kinematics, and tipping next class - Wednesday, November 10th. (Quiz does not include massive pulley problems.) Lab quiz on Massive Pulley Lab on Friday, November 12th.