Download week fourteen

**In Class Activity Plan**

**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.

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

a) Equations

d = Δpos

v = Δpos/Δt

a = Δv/Δt

d = v_{0} + ½at^{2
}v_{f} = v_{0} + at

b) Velocity-time graph

- When does this model apply?

*Answer: *when we have straight line motion

- What is the motion of the wheel?

*Answer: *not moving linearly, but it is movingt

- 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 = v_{0} + ½at^{2} |
θ = ωt + ½ α t |

v_{f} = v_{0} + at |
ω_{f} = ω_{0} + at |

- How should be able to go between the two versions?

a) d = r θ

b) v = r ω

c) a = r α

- Now we can add on the rest of relationships

m | I = åm_{i}r_{i} |

p = mv | L = Iω |

F_{net} = m a |
t = Iα |

E_{klinear} = ½ m v^{2} |
E_{krot} = 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)