phsx213 class n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
PHSX213 class PowerPoint Presentation
Download Presentation
PHSX213 class

Loading in 2 Seconds...

play fullscreen
1 / 36

PHSX213 class - PowerPoint PPT Presentation


  • 119 Views
  • Uploaded on

PHSX213 class. Questions from last time ? Vectors recap Class news Vectors quiz Doing homework Describing Motion (Kinematics) Chapter 2 leading into 4. What is a vector?. A quantity having both size and direction The rate of change of velocity

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PHSX213 class


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
phsx213 class
PHSX213 class
  • Questions from last time ?
  • Vectors recap
  • Class news
  • Vectors quiz
  • Doing homework
  • Describing Motion (Kinematics)
    • Chapter 2 leading into 4.
slide2

What is a vector?

  • A quantity having both size and direction
  • The rate of change of velocity
  • A number defined by an angle and a magnitude
  • The difference between initial and final displacement
  • None of the above
slide3

What is a vector?

  • A quantity having both size and direction
  • The rate of change of velocity
  • A number defined by an angle and a magnitude
  • The difference between initial and final displacement
  • None of the above
slide4

What is the name of the quantity represented as

  • Eye-hat
  • Invariant magnitude
  • Integral of motion
  • Unit vector in x-direction
  • Length of the horizontal axis
slide5

What is the name of the quantity represented as

  • Eye-hat
  • Invariant magnitude
  • Integral of motion
  • Unit vector in x-direction
  • Length of the horizontal axis
diagnostic test
Diagnostic Test
  • Average score: 16.6/30
  • A couple of you did really well – do you want to teach the class ?
  • Scores 20-24. You’ve already got a good grasp of many of the concepts.
  • Scores 15-19. This is about the score I would expect. Room for learning/improvement !
  • Lower scores.
      • Either little previous exposure to physics, or quite a few misconceptions which we’ll need to work on.
      • Please take this positively as a wake-up call that you’ve got a lot to learn/learn properly in this course.
syllabus remarks
Syllabus remarks
  • Will be very similar to last semester at least until the 2nd midterm.
  • Syllabus should be published on Friday.
schedules
Schedules
  • Office Hours.
    • By appointment and,
    • Wed. 2:30 – 4:00 PM ?
  • Extra review sessions on developing problem solving skills
    • Occasionally, Wed. evening 6:00 PM – 7.15 PM ?
  • Normal homework deadlines.
    • Written stuff – in class.
    • Weekly online homework, Friday 6 PM. (will usually be published by Thursday of previous week).
    • Deadline chosen to minimize interference with lab. report deadlines.
mid term exams
Mid-Term Exams
  • Time : 8:00 PM – 9:30 PM
  • Wednesday February 16th
  • Wednesday March 16th
  • Wednesday April 20th
  • 3 classes will be “NO CLASS” days.
  • For sure, March 18th (Friday before Spring Break).
web site
Web Site
  • Now has links to :
    • Registration of your H-iTT clicker
    • Lecture Notes
slide12
Labs
  • Labs are an important part of the course.
  • They will carry 20% of the course credit, and there are severe penalties for missing labs.
  • The MX project is especially important.
  • Most lab. issues need to be discussed with Mr. Curry.
homework
Homework
  • There will be approximately 15 homework assignments.
  • The overall course weight will be between 15 and 20%.
  • Each homework assignment will carry the same weight unless otherwise announced.
  • Most of each homework assignment will be completed online.
homework assignment 1
HRW end-of-chapter problems :

1.12

1.20

2.22

2.56

3.22

To be handed in by Monday in class.

Please use a separate page of paper for each question.

Allows me to give feedback on eg. a subset of the questions.

Draw diagrams (almost always a good idea).

Explain assumptions and use symbols to solve problems algebraically before sticking in numbers.

Homework Assignment 1
timelines
Timelines
  • I should have the HiTT clicker stuff working on Friday.
  • I’ll expect you to have one by Monday.
  • Class homework assignment and online resources page with eGradePlus stuff should be available by this Friday (if not before).
slide20

What are the x- and y-components Cx and Cy of vector

Cx= –3 cm, Cy = 1 cm

Cx= –4 cm, Cy = 2 cm

Cx= –2 cm, Cy = 1 cm

Cx= –3 cm, Cy = –1 cm

Cx= 1 cm, Cy = –1 cm

slide21

What are the x- and y-components Cx and Cy of vector

Cx= –3 cm, Cy = 1 cm

Cx= –4 cm, Cy = 2 cm

Cx= –2 cm, Cy = 1 cm

Cx= –3 cm, Cy = –1 cm

Cx= 1 cm, Cy = –1 cm

worked out example emphasising using symbols for problem solutions
Worked out example emphasising using symbols for problem solutions
  • HRW Chapter 3 question 24
    • An explorer is caught in a whiteout while returning to base camp. He was supposed to travel due north for 5.6 km, but when the snow clears, discovers that he actually traveled 7.8 km at 50º north of due east.
    • How far and in what direction must he travel to reach base camp ?
worked out example emphasising using symbols for problem solutions1
Worked out example emphasising using symbols for problem solutions
  • HRW Chapter 3 question 24
  • Step 1. Draw diagram
  • Step 2. Define variables on diagram
  • Step 3. Write down concept you will use to solve the problem
  • Step 4. Solve the problem algebraically
  • Step 5. Plug in numerical values.
slide25

The slope at a point on a position-versus-time graph of an object is

the object’s speed at that point.

the object’s average velocity at that point.

the object’s instantaneous velocity at that point.

the object’s acceleration at that point.

the distance traveled by the object to that point.

slide26

The slope at a point on a position-versus-time graph of an object is

the object’s speed at that point.

the object’s average velocity at that point.

the object’s instantaneous velocity at that point.

the object’s acceleration at that point.

the distance traveled by the object to that point.

falling dollar
Falling Dollar
  • The reason I’m not planning a European vacation this summer ! (joke)
kinematics describing motion
Kinematics: Describing Motion
  • Reference frame
    • Origin + Co-ordinate axes. x-axis, (x,y)-axes, (x,y,z)-axes
  • Position (location within the co-ordinate axes)
  • Displacement, is defined as (≡) Change in position
  • Velocity ≡ Rate of change in position with time
  • Acceleration ≡ Rate of change in velocity with time
kinematics general case 3 d
Kinematics: General Case (3-D)
  • Reference frame
    • Origin, (x, y, z)-axes
  • Position Vector, r = x i + y j + z k
  • Displacement, ≡ Dr = r2 – r1
  • Instantaneous Velocity, v≡ d r /dt
  • Instantaneous Acceleration, a ≡ d v/dt ≡ d2 r /dt2
  • We will return to these more general definitions when we discuss motion in more than 1-d.

^ ^ ^

kinematics special case 1 d
Kinematics: Special Case (1-D)

Up-down Ball ,

Car demo

  • Reference frame
    • Origin, (x, y, z)-axes
  • Position Vector, x = x i
  • Displacement, ≡ Dx = x2 – x1
  • Instantaneous Velocity, v≡ d x /dt
  • Instantaneous Acceleration, a ≡ d v/dt ≡ d2 x /dt2

^

Draw graphs

draw graphs
Draw graphs
  • Eg. basketball.
  • When is the magnitude of its acceleration the largest ?
what does all this mean
What does all this mean ?
  • Position
  • Displacement (change in position over a time interval)
  • Velocity
    • Is synonymous (to me) with instantaneous velocity
    • average velocity, vave≡ Dr / Dt
    • Speed = magnitude of the velocity.
  • Acceleration
    • Instantaneous acceleration
    • average acceleration, aave≡ Dv / Dt
  • Can something traveling with constant speed be accelerating ?
kinematic equations
Kinematic Equations
  • In general.
    • Will be useful for lab project, MX
  • Specific case of CONSTANT acceleration
meter stick
Meter stick
  • Reaction time measurement
friday
Friday
  • More 1-d kinematics (chapter 2)
  • And start 2-d motion (chapter 4)
    • particularly projectiles
    • uniform circular motion