Physics 121, Sections 9, 10, 11, and 12 Lecture 4 Announcements Lectures available on the web(short version) For over-enrollment please go to the physics office P107 aboratory sessions start next week Gotomywebsitewww.phys.uconn.edu/-rcote Syllabus t homeworks lectures, etc WebAssign gotowww.webassign.netandlogin username: first letter of first name plus last name e.g. John Fernando Lachance: lachance 》 institution: uconn > password: People Soft ID#(without the initial") Physics 121: Lecture 4, Pg 1
Physics 121: Lecture 4, Pg 1 Physics 121, Sections 9, 10, 11, and 12 Lecture 4 Announcements Lectures available on the web (short version) For over-enrollment please go to the Physics office P107 Laboratory sessions start next week Go to my web site www.phys.uconn.edu/~rcote Syllabus + homeworks + lectures, etc. WebAssign: go to www.webassign.net and log in » username: first letter of first name plus last name » e.g. John Fernando Lachance: jlachance » institution: uconn » password: PeopleSoft ID # (without the initial “0”)
Physics 121, Sections 9, 10, 11, and 12 Lecture 3 Today's TopiCs Homework 1: Due Friday Sept 6@ 6: 00PM Ch.1:#4,10,14,19,31,and33. Ch.2:#1.23.37,and63 Chapter 3: Forces and motion along a line Position Velocity: average instantaneous Acceleration average instantaneous Force and acceleration Motion with constant acceleration Falling objects Apparent weight Physics 121: Lecture 4, Pg 2
Physics 121: Lecture 4, Pg 2 Physics 121, Sections 9, 10, 11, and 12 Lecture 3 Today’s Topics: Homework 1: Due Friday Sept. 6 @ 6:00PM Ch.1: # 4, 10, 14, 19, 31, and 33. Ch.2: # 1, 23, 37, and 63. Chapter 3: Forces and motion along a line Position Velocity: average & instantaneous Acceleration: average & instantaneous Force and acceleration Motion with constant acceleration Falling objects Apparent weight
Chapter 3: Position / Displacement Displacement is just change in position △X=X1-X 10 meters 15 meters Xf Joe O △x=5 meters Displacement is a vector quantity a vector quantity has both magnitude and direction a scalar quantity has only magnitude and no direction Physics 121: Lecture 4, Pg 3
Physics 121: Lecture 4, Pg 3 Chapter 3: Position / Displacement Displacement is just change in position. X = xf - xi Displacement is a vector quantity A vector quantity has both magnitude and direction A scalar quantity has only magnitude and no direction 10 meters 15 meters O xi Joe xf x = 5 meters {
Average Velocity The average velocity v during the time interval At is defined as the displacement△ k divided by△t 1 △t 孓t f Physics 121: Lecture 4, Pg 4
Physics 121: Lecture 4, Pg 4 Average Velocity The average velocity v during the time interval t is defined as the displacement x divided by t. f i f i t t x x t x v − − = =
Instantaneous Velocity The instantaneous velocity v is defined as the limit of the average velocity as the time interval At becomes infinitesimally short ≡lim △t→>0 △△ Physics 121: Lecture 4, Pg 5
Physics 121: Lecture 4, Pg 5 Instantaneous Velocity The instantaneous velocity v is defined as the limit of the average velocity as the time interval t becomes infinitesimally short t x v t →0 lim