Lecture Hall Announcements and Logistics

• The lecture hall is large, and items sometimes get left behind.

  • Mentioned rescued and collected items include earbuds, connectors, rings, etc.

Upcoming Test Information

• Test Date: October 7

• Class Schedule:

  • This session is before the class prior to the test, which is adjusted due to the National Day for Truth and Reconciliation.

Test Format

• Structure: Two-stage test starting at 8 AM.

• First part: 45-minute individual test.

• Groups: After the individual test, self-assemble into groups of 3-4 for a group version of the test.

• Variability: Multiple versions of tests to accommodate the large class size.

• Content: Group test will combine elements from individual versions.

Study Resources and Practices

• Best practice: Review previous tests from Physics 112 and past Physics 111 tests.

• Resources:

  • Previous tests are a great way to prepare because they align closely with content covered.

• Weekly Homework: Essential for practice, includes prior test questions and tutorial questions.

• Due date for current week’s homework: Tomorrow by 9 PM.

• Class engagement: Only 122 of 274 students have started the homework.

• Average score trends:

  • Current week average: 43%.

  • Last week average: 92%.

  • Average completion time for current homework: 1 hour 21 minutes.

Test Preparation Strategies

• Focus on conceptual understanding of material.

• Tests will not repeat identical problems from class; students must apply knowledge to new scenarios.

• Expect multiple-choice questions that reward correct reasoning steps.

  • Full marks for correct answers; partial marks for eliminating wrong options.

  • Up to four and a half out of five marks possible without a correct answer if logical reasoning is shown.

  • Objective: Correct understanding and process, not solely the right answer.

Format of Test Questions

• Long answer questions include drawing graphs or diagrams from provided data.

• Number of long answer questions may vary, usually at least one.

• Time management: Instructor tests duration by solving the test themselves and multiplying their completion time by four to gauge student time.

• Group test protocol: All students will form groups including those needing accommodations.

Physics Content Overview

• Initiated discussion on uniform circular motion:

  • Angular velocity: Defined as the rate of change of the angle with respect to time.

  • Uniform Circular Motion: Characterized by constant angular velocity, defined as linear velocity divided by the radius of the circle.

  • Angular position remains consistent, with changes occurring in direction, not speed.

  • Acceleration in Circular Motion: Understood as centipetal or radial acceleration pointing towards the circle's center, even if speed remains constant.

  • Mathematical Relationships:

  • $ext{Linear speed} = r imes ext{angular velocity}$

  • Magnitude of radial acceleration $a<em>r = rac{v^2}{r}$ or $a</em>r = r imes ext{angular velocity}^2$.

Example Problems

• Problem 1: Fly on a record player.

  • Rates of acceleration for the fly as it moves outward depend on angular velocity.

  • As it walks outward, its radial acceleration increases proportionally with distance.

  • Proportional reasoning: $a_r ext{ is proportional to } r$.

• Problem 2: Highway engineering considerations for a curve or ramp.

  • Radii and speed must be designed to accommodate safe navigation at appropriate speeds, considering friction and acceleration requirements.

  • Engineers must ensure enough acceleration can be maintained even on slippery days.

• Problem 3: A roundabout scenario where acceleration changes as speed increases.

  • Quadratic relationship of acceleration based on speed.

  • The importance of understanding how acceleration varies with speed on a circle, emphasizing safety and design.

Conceptual Understanding and Reasoning

• Emphasis on proportional reasoning to simplify problem calculations and avoid unnecessary complexity.

• Explore direct and inverse proportionalities:

  • Directly proportional relationships yield straight-line graphs that pass through the origin, while inversely proportional relationships create hyperbolic graphs.

Clicker Questions

• Incorporate discussions and practical examples to encourage student engagement and ensure understanding.

• Real-time feedback on students’ comprehension through response rates.

Closing Remarks

• The next class will cover material relevant for the upcoming test. Last questions are encouraged.

• Items left in the hall should be claimed from the front desk.