AP Physics B Objectives

Links:

College Board Topic I:
Newtonian Mechanics

Topics:

2. Newton's laws of motion (including friction and centripetal force)
1. Static equilibrium (first law)
2. Dynamics of a single particle (second law)
3. Systems of two or more bodies (third law)

Time Range:
8 weeks

Suggested Teaching Strategies:

• Use inertial balance to introduce mass concept; use airtracks or dynamics carts to illustrate force, mass, and acceleration relationships; use various tricks to demonstrate law of inertia (see core labs).
• Carefully define action and reaction as forces between two objects; demonstrate using two force probes pulling on each other, with inverted graphs of F vs. t showing on computer monitor. Have students create free-body diagrams for a donkey pulling a cart (7 significant action/reaction pairs) or a student sitting in a chair (illustrates confusion between weight, normal force, and identification of the true reaction to weight: earth pulled up by object). Discuss complexities and misconceptions in applying the third law to rocket propulsion (no need for atmosphere; action and reaction can be vaguely defined as rocket pushing gas and vice versa or more precisely defined as exploding gas particles pushing on combustion chamber walls, etc.).
• Check student understanding of laws of motion concepts by having them identify and correct the errors in various statements that contain a misconception or misstatement of one or more of the laws as applied to a situation (e.g. "A ton of feathers on earth has the same inertia as a ton of feathers on the moon.")
• Friction: The core lab will bring out the essential components of the objective, but there will be discrepant data due to the complex nature of friction phenomena. Students may have trouble with surface area concepts, reflecting the confusion in science between apparent and actual contact area, etc.
• Centripetal force: see objective I. E.

Aligned Resources:

• Laws of Motion:
  • Core Lab 3: Forces and Acceleration
  • Core Lab 4: Inertial Balance
  • Core Lab 5: Mass and Acceleration
  • Core Lab 6: The Law of Inertia
  • Core Lab 7: Friction
  • Interactive Physics simulations: atwoods.ip, forcebal.ip, forcubal.ip, forceadd.ip, hangmass.ip, jetplane.ip
  • Case Study: Kansas City Hyatt Regency Hotel Disaster from Failure By Design
  • Videotape: The Mechanical Universe - Inertia
  • Copy of Newton's Principia
• Friction:
  • Interactive Physics simulations: airdrag.ip, carcurve.ip, h20drag.ip, h20vio.ip
  • Videotape: The Mechanical Universe - Friction

Revision Date:
May 2001