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All Class Recordings (Panopto)
source: XKCD (http://xkcd.com/123/)
Zoom link and previous classes
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
Pre-class video to accompany the reading (10:46)
Example: Problem 12-50 (from an older edition of the book, optional)
"Whiteboard" notes from the class
Wed 02/03: Sections 12.4-6
Fri 02/05: Section 12.7
Week 3
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
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)
Recorded solution to Problem 14.67 (12th edition), PDF
Solution to Problem 14-11 (3:48)
Solution to Problem 14-87 (9:22)
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
Introduction (5:30)
Week 8
Mon 03/15: Section 15.3. NO CLASS TODAY; please review the following between now and Wednesday.
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
Week 13
Mon 04/19: Review of Chapter 17 (no class meeting)
Wed 04/21: Section 18.1-5
Fri 04/23: Section 19.1-3
Week 14
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
HW09
HW10: Due in class Monday 2/22 (no take-home part). 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 3/15Wednesday 3/17. SolutionsHW17: All Due Wednesday 3/17. New image added to part B; you can submit on Friday if you prefer. Solutions
HW19: No assignment. Extra credit for everyone!
HW21:
Part A in class, Part BAll Due Monday 3/29. SolutionsHW23: 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 4/19Wednesday 4/21. SolutionsHW26: Due Wednesday 4/21 (i.e, there's no Part A). 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
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