This preview shows pages 1–8. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Physics 112: Lecture 2 Agenda for Today 1D Kinematics 1D Kinematics Average & instantaneous velocity and acceleration Motion with constant acceleration Motion in 1 dimension In 1D, we usually write position as x(t). Since its in 1D, all we need to indicate direction is + or . Displacement in a time t = t 2 t 1 is x = x(t 2 )  x(t 1 ) = x 2 x 1 t x t 1 t 2 x t x 1 x 2 some particles trajectory in 1D 1D kinematics t x t 1 t 2 x x 1 x 2 trajectory Velocity v is the rate of change of position Average velocity v av in the time t = t 2 t 1 is: t V av = slope of line connecting x 1 and x 2 . v av " x ( t 2 ) # x ( t 1 ) t 2 # t 1 = $ x $ t Consider limit t 1 t 2 Instantaneous velocity v is defned as: 1D kinematics... t x t 1 t 2 x x 1 x 2 t so v(t 2 ) = slope of line tangent to path at t 2 . v ( t ) = dx ( t ) dt You are driving on a highway at 80 km/h for 5 h and then through a town at 20 km/h for 30 minutes. What is your average velocity (assume that its all in one direction)? Average velocity: a common mistake Average velocity: a common mistake You are driving on a highway at 80 km/h for 5 h and then through a town at 20 km/h for 30 minutes. What is your average velocity (assume that its all in one direction)? Wrong: (v1 + v2)/2 = 50 km/h Correct: total distance / total time = (400 km + 10 km) / (5 h + 0.5h) = 74.5 km/h Graph of x(t) versus time, whats the average velocity? Defnition oF SPEED: distance traveled...
View
Full
Document
This note was uploaded on 09/29/2008 for the course PHYS 1112 taught by Professor Leclair,a during the Fall '07 term at Cornell University (Engineering School).
 Fall '07
 LECLAIR,A
 mechanics, Acceleration

Click to edit the document details