Lecture 8 PowerPoint

# Lecture 8 PowerPoint - Today Friction Calming Words about...

• Notes
• 40
• 100% (1) 1 out of 1 people found this document helpful

This preview shows page 1 - 10 out of 40 pages.

1 Today Friction Calming Words about the Midterm Q & A 1 Wednesday, 3 October, 12

Subscribe to view the full document.

2 Kinetic Friction Moving objects : kinetic friction force (constant!) μ k : coe ffi cient of kinetic friction n: normal force. Direction is parallel to the sliding surface (perpendicular to the normal force) and opposite the (instantaneous) velocity. v 2 Wednesday, 3 October, 12
3 Typical Problems A book is sliding on a table with an initial speed of 2.5 m/s. Due to friction, the book comes to a stop after 0.5 m. If the book’s mass is 800 g, what is the coe ffi cient of kinetic friction? 3 Wednesday, 3 October, 12

Subscribe to view the full document.

3 Typical Problems A book is sliding on a table with an initial speed of 2.5 m/s. Due to friction, the book comes to a stop after 0.5 m. If the book’s mass is 800 g, what is the coe ffi cient of kinetic friction? A 1.6 kg book (same surface) is sliding with the same initial speed on the same table. What is the sliding distance now? A. 0.125 m B. 0.25 m C. 0.50 m 3 Wednesday, 3 October, 12
Solution Multiple choice part: Acceleration due to friction does not depend On the mass. The friction force itself does. Due to part 1, same acceleration leads to same stopping distance. 4 Wednesday, 3 October, 12

Subscribe to view the full document.

5 5 Wednesday, 3 October, 12
6 Friction You are trying to move a heavy file cabinet. You increase your pushing force until the cabinet finally starts to move. If you keep pushing with the force that was required to set the cabinet in motion, the file cabinet will A. travel at constant speed. B. slow down. C. accelerate. PhET : Friction simulation/forces-and- motion 6 Wednesday, 3 October, 12

Subscribe to view the full document.

6 Friction You are trying to move a heavy file cabinet. You increase your pushing force until the cabinet finally starts to move. If you keep pushing with the force that was required to set the cabinet in motion, the file cabinet will A. travel at constant speed. B. slow down. C. accelerate. F fr F a f s = F a static kinetic PhET : Friction simulation/forces-and- motion 6 Wednesday, 3 October, 12
7 Friction You are trying to move a heavy file cabinet. You increase your pushing force until the cabinet finally starts to move. If you keep pushing with the force that was required to set the cabinet in motion, the file cabinet will A. travel at constant speed.

Subscribe to view the full document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern