AT Cycle 10

🔴❗ 2: W 10/30, 🟡❗ 4: W 10/30, 🔵❗ 8: W 10/30 - moment of inertia problems

Quiz on center of mass, rotational kinematics, and tipping TODAY. 

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

🟥 2: M 11/4 lab, 🟨 4: Th 10/31 lab, 🟦 8: Th 10/31 lab - massive pulley lab

Daily Check-in: rotational dynamics

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.

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

• Large 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 kinetic friction 

• 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.  (Investigate a real life situation in which the torque of friction plays a role.  Do some research on engineering solutions to mitigate or enhance the torque of friction in the real world. What kinds of choices do engineers make to either to reduce, enhance, or control the effects of the torque of friction?)

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:  No Homework Weekend (periods 4 & 8) 10/31  Quiz on moment of inertia Wednesday, November 6th.  Quiz on Massive Pulley Problems and Massive Pulley Lab Thursday, November 14th!  

❤️ 2: T 11/5, 💛 4: M 11/4, 💙8: M 11/4 - ✏️ massive pulley problems (1)

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

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

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

Homework:  These massive pulley problems are due Wednesday, November 8th at 10pm to ✏️ Google Classroom.   Quiz on moment of inertia Wednesday, November 6th.  Quiz on Massive Pulley Problems and Massive Pulley Lab Thursday, November 14th!