In Class Activity Plan

Week 14: Angular Motion & Simple Harmonic Motion

25 min             Whiteboard - Satellite Centripetal Ranking Problem (Word, Pdf)

                        PURPOSE: Practice modeling centripetal acceleration situation.                 

Lots of options here probably want to give one as homework:

20 min             Board Meeting

PURPOSE: Build consensus around modeling centripetal acceleration situation.

Goals:

· Centripetal force is just the net force towards the center

· Need to attend to the radius of the circular path

Additional resources which could be used:

Ferris Wheel Centripetal Force (Word, Pdf)

Centripetal Force Ranking (Word, Pdf)

Circular Motion Problems (Word, Pdf)

20 min             Whiteboard - Ladybug revolution part 1

PURPOSE: Investigate rotational motion, introduce rotational analogs to translational kinematics

Direct students to PhET simulation – Ladybug Revolution (http://phet.colorado.edu/en/simulation/rotation)

                        Give students 10 minutes to explore.

                        Summarize what you have learned on whiteboard.

10 min             Board Meeting

                        PURPOSE: Share what was learned from investigation of simulation

20 min             Whiteboard - Ladybug Revolution part 2

PURPOSE: Develop models for constant rotational motion from graphs of rotational motion.  

                        Directions: Return to the Ladybug Revolution simulation

Use the second tab which shows graphs, use radians.

Answer: What have you learned? What rules can you make? What questions do you have?  On whiteboard.

20 min             Board Meeting

PURPOSE: Reach consensus about equations that describe constant angular acceleration motion.

1. Review the kinematic representations in the basic 1-d constant acceleration model

                                    a) Equations

                                                d = Δpos

                                                v = Δpos/Δt

                                                a = Δv/Δt

                                                d = v₀ + ½at²

                                                v_f = v₀ + at

            b) Velocity-time graph

2. When does this model apply?

Answer: when we have straight line motion

3. What is the motion of the wheel?

Answer: not moving linearly, but it is movingt

4. Create a table of angular variables by analogy

d = Δpos	θ = Δangle
v = Δpos/Δt	ω = Δangle/Δt
a = Δv/Δt	α = Δω/Δt
d = v0 + ½at^2	θ = ωt + ½ α t
vf = v0 + at	ωf = ω0 + at

5. How should be able to go between the two versions?

                        a) d = r θ

b) v = r ω

c) a = r α

            6.  Now we can add on the rest of relationships

m	I = åmiri
p = mv	L = Iω
Fnet = m a	t = Iα
Eklinear = ½ m v^2	Ekrot = ½ I ω^2

25 min             Whiteboard- Helicopter Quantitative Problem (Word, Pdf)

                        PURPOSE: Model situation with constant angular acceleration

20 min             Board Meeting

                        PURPOSE: Build consensus about modeling constant angular acceleration

Homework - Ranking of Theta vs t graph (Word, Pdf) and Rotational speed ranking (Word, Pdf)