February 2026 - Phy121s26

Extra office hours for Exam # 1
by Frank Wolfs 15 Feb '26

15 Feb '26

The following extra office hours will be offered for Exam # 1: Addison Price: 5 - 7 pm, 2/15, POA Thomas Qian: 7 - 9 pm, 2/15, POA Justin Kenneally: 10 am - 12 pm, 2/16, POA Catherine Lei: 12.30 pm - 2.30 pm, 2/16, POA Note: POA stand for the Physics, Optics, and Astronomy library in B&L on the third floor. There will be workshops on Monday and they will be focussed on Exam # 1. Please bring all your questions. Everyone can attend any or all of the workshops. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Solutions to Set 3
by Frank Wolfs 14 Feb '26

14 Feb '26

Attached are the solutions to HW set # 3. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Multiple forces on a single mass
by Frank Wolfs 13 Feb '26

13 Feb '26

My TAs pointed out to me a common misconception about situations where multiple forces act on an object. Many students appear to think that in such a case the net force must be equal to 0 N. This is in general not true. You need to keep in mind that the net force acting on an object is equal to ma. This tells you: 1. If you know that object is not moving or moving with constant velocity, its acceleration is 0 m/s^2 and the net force is 0 N. 2. If you know the object is moving, but you do not know its acceleration, then you cannot assume that the net force is 0 N. If the acceleration is non zero, the net force will be non zero. Please make sure you understand this, especially for Exam #1. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Slides for Thursday
by Frank Wolfs 11 Feb '26

11 Feb '26

Attached are the slides I will use on Thursday. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Quizzes
by Frank Wolfs 11 Feb '26

11 Feb '26

After a few quizzes, it is clear that some of you sometimes experience technical difficulties associated with the software. Since quizzes are for credit, I like to propose the following procedure: 1. If after you answer the first question or questions, the system locks up, make a screenshot of your screen, ensuring that is includes the date and time. 2. Send the screenshot to me via email. 3. I will use the question(s) you were able to answer to determine your quiz grade. In this way, you will not be penalized when the system prevents you from answering additional questions. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Slides for Tuesday
by Frank Wolfs 08 Feb '26

08 Feb '26

Attached are Tuesday’s slides. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Exam # 1
by Frank Wolfs 06 Feb '26

06 Feb '26

For exam # 1, you will receive an equation sheet, a scantron form, 2 blue booklets (questions 11 and 12 need to be answered in one booklet, question 13 needs to be answered in the second booklet), and the actual exam. I have attached a copy of the equation sheet so that you can see what information you are provided with (note: the equations related to gravitational force on page 3 are not needed for Exam # 1 since Chapter 6 is NOT covered on the exam). I also attach a copy of the scantron form. These forms are processed automatically. In order for the form to be processed, you need: 1. To enter your student ID in the bubbles on the top left-hand side of the form. Make sure you know your student ID #! 2. Use a number 2 pencil to fill the bubbles. If you use a pen to complete the form, your entries will not be read. Thus: make sure you bring a # 2 pencil and an eraser if you want to modify your answer on the form. Have a good weekend. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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Tau Beta Pi Drop-In Tutoring Hours Request (fwd)
by Frank Wolfs, Physics and Astronomy, U of R 04 Feb '26

04 Feb '26

I was asked to distribute the following information. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 273 - 3237 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/ ---------- Forwarded message ---------- Date: Tue, 3 Feb 2026 08:00:00 From: Noah Robison <nrobison(a)u.rochester.edu> To: wolfs(a)pas.rochester.edu Subject: Tau Beta Pi Drop-In Tutoring Hours Request Hello Professor Wolfs, I'm Noah Robison, a chemical engineering student and the current Tau Beta Pi Tutoring Chair. As you may have heard, TBP hosts weekly tutoring sessions on Sunday from 1- 4 pm for all students (starting 2/8). During the session, engineering students will be able to provide help for calculus and physics. I wish I could come into your lecture to advertise our service, but my schedule conflicts with the PHYS121 lecture times. I would be deeply grateful if you could flash the tutoring poster (attached to this email) at the beginning of lecture or pin it on your blackboard. Best, Noah Robison

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Slides for Thursday
by Frank Wolfs 04 Feb '26

04 Feb '26

Attached are the slide for tomorrow. Frank Wolfs _____________________________________________________________________ Frank L. H. Wolfs e-mail: wolfs(a)pas.rochester.edu Department of Physics and Astronomy University of Rochester B&L 203A, RC Box 270171 fax: (585) 275 - 8527 284 Hutchison Rd. phone: (585) 210 - 3271 Rochester, NY 14627 http://teacher.pas.rochester.edu/

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