2.1 Systems and Center of Mass

Describe the properties and interactions of a system.

• System properties are determined by the interactions between objects within the system.
• If the properties or interactions of the constituent objects within a system are not important in modeling the behavior of the macroscopic system, the system can itself be treated as a single object.
• Systems may allow interactions between constituent parts of the system and the environment, which may result in the transfer of energy or mass.
• Individual objects within a chosen system may behave differently from each other as well as from the system as a whole.
• The internal structure of a system affects the analysis of that system.
• As variables external to a system are changed, the system’s substructure may change.

Describe the location of a system’s center of mass with respect to the system’s constituent parts.

• For systems with symmetrical mass distributions, the center of mass is located on lines of symmetry.
• The location of a system’s center of mass along a given axis can be calculated using the equation
• A system can be modeled as a singular object that is located at the system’s center of mass. BOUNDARY STATEMENT AP Physics 1 only expects students to calculate the center of mass for systems of five or fewer particles arranged in a two-dimensional configuration or for systems that are highly symmetrical. AP Physics 1: Algebra-Based Course and Exam Description Force and Translational Dynamics UNIT 2