ESCI 2150 (Dynamics)

Are you getting a permission error when you try to open a file? Click here, first.

Jump to:

source: XKCD (http://xkcd.com/123/)

    • Zoom link and previous classes

      • We will use this link for all classes (Spring 2021)

      • Meeting ID: 930 3809 4543

      • Password: hibbeler

      • All classes will be recorded and (eventually) uploaded to Panopto (here).

    • Syllabus (Spring 2021)

    • Course internal website (Spring 2021) *

Daily Readings (all readings out of Hibbeler, Engineering Mechanics: Dynamics, 14th Edition). Also, prior to 2016, ESCI 2150: Dynamics was ESCI 211: Dynamics, so don't let the labels on the old videos scare you.

  • This Week

      • Mon 05/03: Review of Chapters 17-19

      • Wed 05/05: Review of Chapters 17-19

      • Fri 05/07: Midterm 3

    • Week After That (Week of 5/10)

      • Mon 05/10: Team Presentations

      • Wed 05/12: Final Exam (2:00pm-3:50pm)

  • Previous Weeks

    • Week 1

      • Fri 01/29: Section 12.2: Introduction to Motion (7:18) optional

    • Week 2

      • Mon 02/01: Section 12.3: Erratic Motion

      • Wed 02/03: Sections 12.4-6

        • Pre-class videos:

          • Section 12.4: Curvilinear (Vector) Motion (3:46)

          • Section 12.5: Rectangular/Cartesian Coordinates (10:43)

        • optional but strongly recommended

          • Section 12.6: Projectile Motion (6:17)

            • Throwing the Ball over the Barn (6:02)

            • Skeet Shooting (4:22)

      • Fri 02/05: Section 12.7

        • Introductory Video (3:29)

        • Derivation of Normal-Tangential Coordinates (10:56)

        • Example Problems - please watch the first two, at least

          • Problem 12-118 (7:39)

          • Problem 12-122 (9:18), includes discussion of radius of curvature calculation

          • Problem 12-133 (12:15)

    • Week 3

      • Mon 02/08: Section 12.8 (Cylindrical Coordinates)

      • Example 12.20 (10:00) optional but recommended

      • Problem 12-168 (6:24) optional but recommended

      • Wed 02/10: Section 12.9 (Geometric Constraints and Pulleys)

      • Fri 02/12: Section 12.10 (Relative motion) and catching our breath

    • Week 4

      • Mon 02/15: Sections 13.1-4: Force

      • Important (written) rant on units.

      • In the rational (metric) system, the unit of force is the Newton, the unit of mass is the kilogram, and the "unit" of acceleration is the meter/second2. Therefore, (1 kg) x (1 meter/second2) = (1 Newton)

      • In the irrational (American) system, the unit of force is the pound, the unit of mass is the slug, and the "unit" of acceleration is the foot/second2. Therefore, (1 slug) x (1 foot/second2) = (1 pound).

      • The unit called "pound mass" is an abomination and will not be used in this class. That so-called unit only confuses things because one never knows when or whether to divide or multiply by 32.2. Therefore, in this class (and in all polite society), the pound always and only refers to force (including weight). One must divide the weight by the gravitational constant to arrive at mass, which will always be the delightfully-named slug.

    • And now back to the course material.

        • Introduction to the Chapter (11:54)

        • There will be online class "live" at 2:10pm. See the link above.

      • Wed 02/17: Happy Presidents' Day (observed). No class

      • Fri 02/19: Section 13.5 & 13.6: Force-balance in normal-tangential & cylindrical coordinates. There is no prepared lecture for Friday. Instead, here are a lot of sample problems (mostly from the old book).

      • Cartesian coordinates

          • Collar sliding on pole with spring (9:07). Be sure you understand how to calculate the force generated by a linear spring, especially that we care about deflection from unstretched length, not the total length of the spring. Also, would this problem be easier to solve in cylindrical coordinates?

      • Normal-tangential coordinates

          • Man on chair on pole - don't try this at home (7:09). Be sure you understand what "about to lose contact" means for the magnitude of the normal force.

          • Child on swing (5:23). Notice that by using normal tangential coordinates, we can immediately solve for the value that interests us (rate of change of speed). This is not an accident.

          • Child on spinning wheel (4:12). Ask yourself: "Why was this problem done in normal-tangential coordinates, when we solved the next problem using cylindrical coordinates?"

      • Cylindrical coordinates

          • Block on a spinning wheel (5:29). Be sure you understand why the static friction force can have a magnitude of anything between 0 and (μ x normal force).

    • Week 5

      • Mon 02/22: Examples in Chapter 13

      • Wed 02/24: Examples in Chapter 13

      • Fri 02/26: Sections 14.1-3: Introduction to Energy Methods

        • Introduction to Chapter 14 (10:58)

        • Work (6:06)

    • Week 6

      • Mon 03/01: Sections 14.4-14.6: Potential Energy and Power

        • Pre-class video to accompany the reading:

          • Kinetic and Potential Energy (8:19)

        • Video to watch in class: Full-sized loop-the-loop example from Fifth Gear (4:57).

        • Worked problems (Problems are from the 12th edition - gray cover)

      • Wed 03/03: Review of Chapters 12-13

      • Fri 03/05: Midterm 1 (Chapters 12-13)

    • Week 7

      • Mon 03/08: Chapter 14 Problems

      • Wed 03/10: Section 14.4 (Power)

      • Fri 03/12: Section 15.1-2

    • Week 8

      • Mon 03/15: Section 15.3. NO CLASS TODAY; please review the following between now and Wednesday.

        • Ball bearing collisions: basics of momentum & impact equation. (6:36)

        • Impact between two objects: effects of varying the coefficient of restitution. (12:31)

        • Collision of a ball with a wall (7:41)

      • Wed 03/17: Section 15.4

      • Fri 03/19: Review of Chapter 15

    • Week 9

      • Mon 03/22: Section 16.1-4

      • Wed 03/24: Midterm 1 Review

      • Fri 03/26: Section 16.5-6

    • Week 10

      • Mon 03/29: Section 16.7

      • Wed 03/31: Section 16.8

        • Coriolis Effect Video (3:01)

      • Fri 04/01: Good Friday (no class)

    • Week 11

      • Mon 04/05: Review of Chapter 16

      • Wed 04/07: Review of 14-16

      • Fri 04/09: Midterm 2 (Chapters 14-16) Solutions

    • Week 12

      • Mon 04/12: Section 17.1-3

        • Section 17.1: A review of moments about mass center, instantaneous centers and the parallel axis theorem (and all in only 13:44!)

        • Note: This section will not be reviewed in class, but you are expected to understand it. Specifically:

          • You need to know that mass moment of inertia (I) is the rotational equivalent of mass

          • You need to know how it is calculated. More importantly, you need to know how to look up I for the shapes found inside the back cover of the book!

          • You need to know how to use radius of gyration. [Hint: IG=m kG2]

        • Section 17.2: A brief explanation of what's going on (9:17)

        • Section 17.3: Example 17.6 (12:16).

      • Wed 04/14: Section 17.4

      • Fri 04/16: Section 17.5

        • Problem 17-107 (12th edition): cylinder rolling on truck (16:13). I make an error at about the 4:30 mark. Can you spot it? (I notice/correct the error a few minutes later.)

        • Spool unwinding in free fall (9:30)

    • Week 13

      • Mon 04/19: Review of Chapter 17 (no class meeting)

      • Wed 04/21: Section 18.1-5

        • Overview of Chapter 18 (3:25)

        • Why no work is done when rolling-without-slipping!?!? (18:30)

        • Example Problems

        • Ball Rolling Downhill, different shapes (11:36)

        • Wheel and spring - Example 18.3, p. 465 (11:38)

      • Fri 04/23: Section 19.1-3

    • Week 14

      • Mon 04/26: Section 19.1-2

        • Problem 19-8 [problem 19-5 in 12th edition]. This is one of my favorite problems in Chapter 19, and yes, you should take that as a hint. (9:33)

        • Problem 19-11 (7:34)

        • Problem 19-14 (8:04)

      • Wed 04/28: Section 19.3

      • Fri 04/30: Chapter 19 Review

Assignments. Recorded solutions to the homework will be in the "Homework-SP2021" Panopto folder (which you can also access from the sidebar); the written (PDF) solutions are linked below. If you will submit your assignments electronically, please use a shared Google Drive folder (instructions on how to set that up are here.)

  • HW08

      • Part A (the "in-class" portion) should be completed online (click through to see it). Please complete by midnight (Monday 2/15).

      • Part B (due Monday [!] 02/22). Solutions

  • HW09

    • HW10: Due in class Monday 2/22 (no take-home part). Solutions

    • HW11: Part A in class, Part B Due Friday 2/26. Solutions

    • HW12: Part A in class, Part B Due Monday 3/01. Solutions

    • HW13: Part A in class, Part B Due Wednesday 3/03. Solutions

    • HW14: Part A in class, Part B Due Wednesday 3/10. Solutions

    • HW15: Part A in class, Part B Due Friday 3/12. Major correction to part B. Solutions

    • HW16: Part A in class, Part B Due Monday 3/15 Wednesday 3/17. Solutions

    • HW17: All Due Wednesday 3/17. New image added to part B; you can submit on Friday if you prefer. Solutions

    • HW18: Part A in class, Part B Due Friday 3/19. Solutions

    • HW19: No assignment. Extra credit for everyone!

    • HW20: Part A in class, Part B Due Wednesday 3/24. Solutions

    • HW21: Part A in class, Part B All Due Monday 3/29. Solutions

    • HW22: Part A in class, Part B Due Monday 4/5. Solutions

    • HW23: Part A in class, Part B Due Wednesday 4/14. Solutions (Problem 8 has been corrected)

    • HW24: Part A in class, Part B Due Friday 4/16. Solutions (Problem 6 has been corrected)

    • HW25: Part A in class, Part B Due Monday 4/19 Wednesday 4/21. Solutions

    • HW26: Due Wednesday 4/21 (i.e, there's no Part A). Solutions

    • HW27: Part A in class, Part B Due Friday 4/23. Solutions

    • HW28: Part A in class, Part B Due Monday 4/26. Solutions

    • HW29: Part A in class, Part B Due Wednesday 4/28. Solutions

    • HW30: Part A in class, Part B Due Friday 4/30. Solutions

  • Notes on Homework

      • Please show your work (at least set up the governing equations and key steps to reach the solution)

      • Make sure you include signs and directions when dealing with vectors

      • Please box / show your answers, and restate them at the end of the problem

      • Missing units are -1/4 point per instance (!!! Yes, you can earn negative points on a problem.)

      • Grading scale

        • 5 = Correct answer, work shown

        • 4 = Incorrect answer, but small errors (math, typos)

        • 3 = Incorrect answer, but most of the process is correct

        • 2 = Incorrect answer with significant conceptual errors (or only partially complete)

        • Correct answer with no work shown

        • 1 = Problem was started, but not completed

        • 0 = Problem not submitted

Project