Announcements: 1.Labs start in the second week of classes. 2.Diagnostic test on Friday, August No class on Monday, September 1, Labor Day 4.PreClass quiz on WebCT available now, due by 8pm on Tuesday, September 2 5.Homework is due in class on Wednesday, September 3. 6.If you need help, come to my office hours M W 10-11am, T Th 1-3pm or send me through WebCT 7.Computation class starts in the second week of classes.

Average speed and velocity for 1-d motion Speed is never negative. Your speedometer shows a positive speed even when you are driving in reverse. The velocity contains information on the direction of the motion. For 1-d motion it can be positive, negative, or zero.

An object goes from one point in space to another. After it arrives at its destination, its displacement is: 1.either greater than or equal to 2.always greater than 3.always equal to 4.either smaller than or equal to 5.always smaller than 6.either smaller or larger than the distance traveled.

Average velocity in the time interval t 1 to t 2

Instantaneous velocity at time t 1

Velocity describes how position changes with time. Acceleration describes how velocity changes with time.

Important example for motion at constant acceleration: Near the surface of the earth, neglecting air resistance, all objects move with the same constant acceleration.