4.1a All energy transfers are governed by the law of conservation of energy.*
4.1b Energy may be converted among mechanical, electromagnetic, nuclear, and ther-
4.1c Potential energy is the energy an object possesses by virtue of its position or
condition. Types of potential energy include gravitational* and elastic*.
4.1d Kinetic energy* is the energy an object possesses by virtue of its motion.
4.1e In an ideal mechanical system, the sum of the macroscopic kinetic and potential
energies (mechanical energy)is constant.*
4.1f In a nonideal mechanical system, as mechanical energy decreases there is a
corresponding increase in other energies such as internal energy.*
4.1g When work* is done on or by a system, there is a change in the total energy* of the
4.1h Work done against friction results in an increase in the internal energy of the system.
4.1i Power*is the time-rate at which work is done or energy is expended.
4.1j Energy may be stored in electric* or magnetic fields. This energy may be trans-
ferred through conductors or space and may be converted to other forms of energy.
4.1k Moving electric charges produce magnetic fields.The relative motion between a
conductor and a magnetic field may produce a potential difference in the conductor.
4.1l All materials display a range of conductivity.At constant temperature,common
metallic conductors obey Ohm s Law*.
4.1m The factors affecting resistance in a conductor are length, cross-sectional area,
4.1n A circuit is a closed path in which a current*can exist.(Note:Use conventional
4.1o Circuit components may be connected in series* or in parallel*.Schematic dia-
grams are used to represent circuits and circuit elements.
4.1p Electrical power*and energy* can be determined for electric circuits.