1. Physics Chapter 2 Notes

2. Chapter 2 2-1 Mechanics  Study of the motion of objects Kinematics  Description of how objects move Dynamics  Force and why objects move as they do

3. Chapter 2 Translational Motion  Move without rotation Frame of reference  Usually with respect to earth Coordinate axes  X & Y

4. Chapter 2 Displacement  Change in position  Example: walk 100m, reverse 20m = 80m displacement Vectors Magnitude and direction

5. Chapter 2 2-2 Average speed  The distance traveled along its path divided by the time it takes to travel this distance  Average Speed = Distance traveled  time elapsed Velocity  Magnitude and direction  Speed with direction  Average velocity = Displacement  time elapsed v = ∆x/∆t = (x 2 -x 1 )/(t 2 -t 1 )

6. Chapter 2 2-3 Instantaneous Velocity The average velocity over an infinitesimally short time interval

7. Chapter 2 2-4 Acceleration  change in velocity over time Average Acceleration = change of velocity  time elapsed a = ∆v/∆t = (v 2 -v 1 )/(t 2 -t 1 )

8. Chapter 2 2-5 Uniform acceleration Constant acceleration, constant direction  v = v o + at  x = x o + v o t + 1/2 at 2  v 2 = v o 2 + 2a(x-x o )

9. Chapter 2 2-6 Problem solving  Read  Draw diagram  Write down known or given information  Think about physics principles  Choose equations with one unknown  Solve calculation  Ask if answer is reasonable  Check units

10. Chapter 2 2-7 Free fall Galileo  Objects fall with same acceleration d  t 2 with absence of air resistance Acceleration due to gravity on earth g = 9.8 m/s 2 or g = 32 ft/s 2 Calculations - assume start point is y=0 Use same equations with x=y and a=g

11. Chapter 2 2-8 Graphical analysis of linear motion Slope =  y   x The slope of a curve at a point is equal to the slope of the tangent to the curve at that point Graph velocity vs. time Displacement is equal to area under curve between two times