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AP Physics B Curriculum Page
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College Board Topic I:
Newtonian Mechanics
Topics:
- Circular motion and rotation
- Uniform circular motion
- Torque and rotational statics
Time Range:
3 weeks
Suggested Teaching Strategies:
- Data-gathering on centripetal force can pose safety hazards, so one version of the core lab substitutes careful thought about an apparatus and a later geometric proof of the equation. For safety reasons, that version of the core lab also calls for a demonstration of released circular motion using a puck on an air table, rather than having students release circling stoppers. Another version of core lab uses force probes to obtain quantitative relationship.
- Emphasize that centrifugal force is fictitious and used to explain inertial effects; in an inertial frame of reference, there is only centripetal force and acceleration. Illustrate the inward acceleration using an accelerometer: put a fishing bob in a jar or flask of water; the bob always moves in the direction of the acceleration due to the water's greater mass and inertia; spin holding the accelerometer to see the bob swing inward.
- Illustrate the distinction between angular and linear speed using a phonograph.
- Illustrate vertical circles using a cup of water spun on a string-mounted platform; use this to lead into critical speed calculation and segue later into orbital velocity.
- For torque, do a lab where students place weights on a meterstick with fulcrum. Have them discover the relationships between force and distance so that the stick balances, and use their formula to predict placement of a weight to restore balance.
Aligned Resources:
Revision Date:
December 2003
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