Section 1: Rotational Motion http://www.cleanvideosearch.com/media/action/yt/watch?videoId=_36MiCUS1ro http://www.cleanvideosearch.com/media/action/yt/watch?videoId=Wda7azMvabE

Something Cool at the Exploratorium

Coriolis Affect

Angular Displacement: Angle an object passes through while in circular motion.

Measuring Rational Motion Tangential Velocity (Vt): Velocity of an object that is traveling in a curved path. Vt=∆s/t where s = θ·r 2) Tangential Acceleration (at): Acceleration of an object as it travels along a curved path. at=∆Vt/t

Sample Calculation 1: Find the tangential velocity of a racecar that travels half way around a racetrack with a 100 meter radius in 5 seconds.

What direction will the block go when released? Conclusion: The block will go in direction _____ because the motion of the block at any given point in time is __________ to the curve of its path.

ω = Vt/r or ω = ∆θ/t α = ∆ω/t Angular Speed (ω: rad/s): How quickly an object spins about its center of rotation. ω = Vt/r or ω = ∆θ/t Angular Acceleration (α): Rate of change in angular speed. α = ∆ω/t

Problem: Find the angular speed in RPS: Find the angular speed in rad/s: What is the tangential velocity of the outside of the gear?

Find the angular speed and velocity

Activity/Quiz: (10 pts) Tank and distance Find the wheel angular speed: Find the wheels tangential velocity: How far will it go in 15 seconds:

Angular speed properties: All points on a fixed rigid object has the same angular speed.

2) Angular speed of a racecar around a racetrack can be increased by increasing the ______ and decreasing the _____

Reflection Which point has the greatest tangential velocity? Which point has the greatest angular speed?

Three cars are traveling around a curve traveling 90 mi/hr. Which car has the greatest angular speed? Which car has the greatest tangential velocity?

Gears: Gear Speeds: ωB = ωA (RA/RB) If gear A spins at 10 rad/s and has a radius of .4m, find the following if gear B has a radius of 1.2m: Tangential Velocity of gear B: Angular speed of gear B: Gears: Which gear has the greatest tangential velocity? Which gear has the greatest angular speed?

Gear and Chain:

Gear to Chain = Gear to Gear relative to tangential velocity

Reflection from worksheet:

Worm gear is spinning at 50 RPM:

Motor is spinning at 1750 RPM

Find the angular speed of gear C if the driving gear is spinning at 5 RPM:

Short Quiz: 1) Find gear A’s angular speed: 2) Find gear A’s tangential velocity: 3) Find gear D’s angular speed using ratio

Rotational Motion Quiz: (3pts each)

The following guy is spinning three objects that are all connected to the same string. Which location has the greatest tangential velocity? Which location has the greatest angular speed?

Three cars round a bend at 30m/s. 3) Which car will make it around the bend first? 4) Which car has the greatest tangential velocity? 5) Which car has the greatest angular speed?

Advance Quiz: 20 pts Gear and Gears Find the angular speed of gear 1: Find the angular speed of gear 2: Find the tangential velocity: Find the distance it goes in 50 seconds:

Teacher reflections: Conceptual students need hands on activities relative to the circular geometrics. They also need more practice with basic in class text problems. Gears problems were not addressed due to time constraints.