Download week two

**In Class Activity Plan**

Week Two: Practice Constant Motion & Introduce Motion Maps, Develop Constant Acceleration Model

** 30 min – ****Constant Motion Activity** (Word, Pdf)

PURPOSE: Introduce Motion Maps; practice with representations

Goals for the students to focus on:

- Coordination of representations (Consistency between the p-t graph, the v-t graph, and the frame of reference)
- Application of constant velocity model rules (see the instructor guide from Week 1)
- Introduce Motion Maps (if not done previously)

*See Motion Maps.doc for more information
(you can hand this out to students after the discussion if you like)*

*Points (dots) represent position at a time*

*Arrows represent velocity (speed and direction)*

**Seed:
**On #2 point out that you don’t know the initial position from a v-t graph. Get two groups to put different initial positions.

**10 min – Whiteboard – Constant Motion Activity**

*Note: Assign individual groups to whiteboard their models for specific problems. Have two groups present that have different answers for #1 and two more groups #2.*

**20 min – Board Meeting
**PURPOSE: Share problem solutions, provide feedback on solutions.

*Emphasize internal consistency within problem solution – This means both the instructor and students should look for the model for each group is consistent. Note that all groups doing a particular problem do not need to have identical solutions, they may vary by choice of reference frame, so it depends on how each group has chosen to model the situation.*

**120 min – Investigating Constant Acceleration Lab** (Word, Pdf)

PURPOSE: Extend graphs and motion maps to now include constant accelerated motion.

Video Examples: (Group 1, Group 2)

Logistic Notes:

- Need to add acceleration graph to Logger Pro
- Hurry students through page 1 & 2, don’t let them spend too much time here
- If the lab is too long for a single day, you may want to do a whiteboard discussion after page 8
- If graphs are too noisy, the instructor can do some examples with fan carts to get the point across

Seed:

- Is it OK to throw out the noise in the data?
- Is acceleration actually constant?
- How are position graphs in trials 1-4 different (concavity)?
- Previously, the slope of the position vs. time graph gave the velocity, is this still true?
- Consider: How do we now modify this statement “The slope of the position vs. time graph equals the velocity”? (Answer: We have to insert “at any point”)
- Are any of the trials 1-4 similar with respect to velocity graphs?
- Can velocity be negative?
- Can acceleration be negative?
- Can you have a negative acceleration, but be speeding up?
- Table of (1) Direction of Motion (2) Direction of acceleration and (3) Speeding up/Slowing down

**15 min – Whiteboard – Investigating Constant Acceleration Lab
**PURPOSE: Summarize results from constant acceleration investigation.

Video Examples: (Whiteboarding)

- What did you learn?

Note: “Learning” does not require evidence. Possible examples of learning statements:

– Definitions

– Using the equipment

– Experimental technique (e.g. minimizing the error)

- What rules can you make (and what evidence do you have to support those rules)?

Note: If you look ahead to the discussion section, as the instructor you’ll want to make sure all of those rules appear on various whiteboards

- What questions do you still have?

**45 min – Board Meeting**

PURPOSE: Establish consensus on defined terms, and rules for interpreting graphs and motion maps with constant acceleration.

Video Examples: (Discussion 1, Discussion 2)

*Note: Today is a day that you will be in the center of the circle many times (thus, you may not want to wear a short skirt this day)*

Terms to define:

- Acceleration must include:

- Motion maps have changing lengths of arrows

– Velocity-time graphs are straight lines, not necessarily horizontal

- Get rid of deceleration

* Here you might ask what deceleration means, and you get multiple answers such as slowing down and negative acceleration, and then you point out this is not a helpful term*

Rules – constant acceleration model

- When constant acceleration, constant v rules don’t apply

Which rules still apply?

– Slope of position tells us velocity (Note: derivative = slope of the tangent line

– Area under the curve of velocity tells us the change in position

- Acceleration is the slope of velocity-time graph

Direction

a = ∆v/∆t

- Area under the curve of acceleration graph tells us change in velocity

∆v = a∆t

- In the Motion Maps the change in length of velocity vector is proportional to the acceleration
- Chart of relation between direction of velocity, direction of acceleration, and speeding up/slowing down

**60 min – Accelerated Motion In-Class Activity** (Word, Pdf)

PURPOSE: See relationships between representations and apply rules of constant acceleration model

*Note: Finish for homework. This is getting turned in for a grade.*

*Goals:*

- Coordination of representations (Consistency between the p-t graph, the v-t graph, the a-t graph, motion map, and frame of reference)
- Application of constant acceleration model rules