1. In this chapter we will only look at motion along a line (one dimension). Motion can be forward (positive displacement) or backwards (negative displacement) Chapter 2: Motion in One Dimension-continued Reading assignment: Chapter 3 Homework 3 (due Friday, Sept. 2, 2005, 10 pm): (Chapter 3) Q4, 6, 11, 24, 39, 54

2. TUTOR & HOMEWORK SESSIONS This year’s tutors: Jerry Kielbasa, Matt Rave, Christine Carlisle All sessions will be in room 103 (next to lecture room). Tutor sessions in semesters past were very successful and received high marks from students. All students are encouraged to take advantage of this opportunity. MondayTuesdayWednesdayThursdayFridaySaturdaySunday 4-6 Jerry 5-7 Christine 4-6 Jerry 5-7 Matt 3-5 Jerry 6-8 Christine 6-8 Matt

3. Review from Friday: Displacement x, velocity v, acceleration a a = dv/dt = d 2 x/dt 2, and v = dx/dt. x is slope of v-graph, v is slope of a-graph.

4. One-dimensional motion with acceleration * as function of time Velocity as function of ______________ Derivations: Book pp. 44-46 * as function of time ____________ as function of time and velocity

5. Black board example 2.7 (see book) Spotting a police car, you brake a Porsche from a speed of 100 km/h to speed 80 km/h during a displacement of 88.0 m at a constant acceleration. (a)What is your acceleration? (b) How long did it take to slow down?

6. Notice that acceleration and velocity often point in different directions!!!

7. Black board example 2.8 A car traveling at constant speed of 45.0 m/sec passes a trooper hidden behind a billboard. One second after the speeding car passes the billboard, the trooper sets out from the billboard to catch it, accelerating at a constant rate of 3.00 m/s 2. (a) How long does it take her to overtake the car? (b) How far has she traveled?

8. Freely falling objects In the absence of air resistance, all objects fall towards the earth with the same constant acceleration (a = -g = -9.8 m/s 2 ), due to gravity

9. General Problem-Solving Strategy Conceptualize __________________________________ Categorize__________________________________ Analyze __________________________________ Finalize __________________________________

10. Black board example 2.9 A stone thrown from the top of a building is given an initial velocity of 20.0 m/s straight upward. The building is 50 m high. Using t A = 0 as the time the stone leaves the throwers hand at position A, determine: (a)The time at which the stone reaches its maximum height. (b) The maximum height. (c) The time at which the stone returns to the position from which it was thrown. (d) The velocity of the stone at this instant (e)The velocity and and position of the stone at t = 5.00 s.

11. Review: Displacement x, velocity v, acceleration a a = dv/dt = d 2 x/dt 2, and v = dx/dt. Know x, v, a graphs. x is slope of v-graph, v is slope of a- graph. For constant acceleration problems (most problems, free fall): Equations on page 36-7 (const. Acceleration & free fall). Free fall