1 / 37

Welcome to

Physics B. Welcome to. Dr. Bertrand pbertrand@ortn.edu 425-9500 x 2568 http://moodle521.occ.utk.edu. 3-Ring Binder (with sections). Notes Homework Quizzes and Tests Lunch Bunch Notes (Physics B only) Lunch Bunch Homework (Physics B only) Lunch Bunch Quizzes and Tests (Physics B only).

berny
Download Presentation

Welcome to

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physics B Welcome to

  2. Dr. Bertrand pbertrand@ortn.edu 425-9500 x 2568 http://moodle521.occ.utk.edu

  3. 3-Ring Binder (with sections) • Notes • Homework • Quizzes and Tests • Lunch Bunch Notes (Physics B only) • Lunch Bunch Homework (Physics B only) • Lunch Bunch Quizzes and Tests (Physics B only)

  4. Kinematics The branch of mechanics that studies the motion of a body without caring about what caused the motion.

  5. Particle • Has position and mass. • Has NO size or volume. • Located at one point in space.

  6. Position • Location of a particle in space. • One dimension (x) • Two dimensions (x,y) • Three dimensions (x,y,z)

  7. 1-Dimensional Coordinates x = 1 m -1 0 1 2 3 X (m)

  8. Distance • The total length of the path traveled by an object. • Does not depend upon direction. • “How far have you walked?”

  9. xf = -1 m 1-Dimensional Coordinates Distance moved by particle is 2 meters. xi = 1 m -1 0 1 2 3 X (m)

  10. Displacement • The change in position of an object. • Depends only on the initial and final positions, not on path. • Includes direction. • “How far are you from home?”

  11. Displacement • Represented by x. • x = x2 - x1 where x2 = final position x1= initial position

  12. xf = -1 m 1-Dimensional Coordinates Distance moved by particle is 2 meters. Displacement of particle is -2 meters. xi = 1 m -1 0 1 2 3 X (m)

  13. Distance vs Displacement B 100 m displacement 50 m distance A

  14. Average Velocity Laboratory Today Do lab in assigned groups. Record results in table at front of room. Finish lab write-up at home if necessary.

  15. Average Speed save = d t Where: save = rate (speed) d = distance t = elapsed time

  16. Average Velocity vave = ∆x ∆t Where: vave = average velocity ∆x = displacement (x2-x1) ∆t = change in time(t2-t1)

  17. Velocity vs Speed • Average speed is always positive. • Average velocity can be positive or negative depending direction. • Absolute value of velocity can be used for speed if the object is not changing direction.

  18. B x Dx A Dt t Average Velocity Vave = Dx/Dt, or the slope of the line connecting A and B.

  19. A x B Dx Dt t Average Velocity Vave = Dx/Dt; still determined by the slope of the line connecting A and B.

  20. x t Instantaneous Velocity B Determined by the slope of the tangent to a curve at a single point.

  21. Acceleration • A change in velocity is called acceleration. • Acceleration can be • speeding up • slowing down • turning

  22. Uniformly Accelerated Motion • In Physics B, we will generally assume that acceleration is constant. • With this assumption we are free to use this equation: a = ∆v ∆t

  23. Units of Acceleration The SI unit for acceleration is m/s2.

  24. Sign of Acceleration Acceleration can be positive or negative. The sign indicates direction.

  25. General Rule If the sign of the velocity and the sign of the acceleration is the same, the object speeds up. If the sign of the velocity and the sign of the acceleration are different, the object slows down.

  26. Accelerating objects… Note: each of these curves has many different slopes (many different velocities)! x t

  27. Pick the constant velocity graph(s)… x v A C t t v x B D t t

  28. Another accelerating object. x Another tangent. Another instantaneous velocity! t The tangent touches the curve at one point. Its slope gives the instantaneous velocity at that point.

  29. x v a t t t Acceleration vs time Position vs time Velocity vs time Summary:Constant position graphs

  30. x v a t t t Acceleration vs time Position vs time Velocity vs time Summary:Constant velocity graphs

  31. x v a t t t Acceleration vs time Position vs time Velocity vs time Summary:Constant acceleration graphs

  32. Summary v = vo + at x = xo + vot + 1/2 at2 v2 = vo2 + 2a(∆x)

  33. Free Fall • Occurs when an object falls unimpeded. • Gravity accelerates the object toward the earth.

  34. Acceleration due to gravity • g = 9.8 m/s2 downward. • a = -g if up is positive. • acceleration is down when ball is thrown up EVERYWHERE in the balls flight.

  35. Summary v = vo - gt x = xo + vot - 1/2 gt2 v2 = vo2 – 2g(∆x)

  36. Symmetry • When something is thrown upward and returns to the thrower, this is very symmetric. • The object spends half its time traveling up; half traveling down. • Velocity when it returns to the ground is the opposite of the velocity it was thrown upward with. • Acceleration is –9.8 m/s2 everywhere!

  37. Determination of Your Reaction Time! Get in lab groups. Drop meter stick between forefinger and thumb of another person. See where the person grabs the stick. Calculate reaction time!

More Related