Physics Chapter 2 Notes

1. Physics Chapter 2 Notes

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 Chapter 2

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

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

5. 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 = (x2-x1)/(t2-t1) Chapter 2

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

7. 2-4 • Acceleration • change in velocity over time • Average Acceleration = change of velocity time elapsed • a = ∆v/∆t = (v2-v1)/(t2-t1) Chapter 2

8. 2-5 • Uniform acceleration • Constant acceleration, constant direction • v = vo + at • x = xo + vot + 1/2 at2 • v2 = vo2 + 2a(x-xo) Chapter 2

9. 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 Chapter 2

10. 2-7 Free fall • Galileo • Objects fall with same acceleration d t2 with absence of air resistance • Acceleration due to gravity on earth g = 9.8 m/s2 or g = 32 ft/s2 • Calculations - assume start point is y=0 • Use same equations with x=y and a=g Chapter 2

11. 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 Chapter 2