J

　　Joule

　　The joule (J) is the unit of work and energy. A joule is 1 N · m or 1 kg · m2/s2.

　　K

　　Kelvin

　　A scale for measuring temperature, defined such that 0K is the lowest theoretical temperature a material can have. 273K = 0oC.

　　Kepler’s First Law

　　The path of each planet around the sun is an ellipse with the sun at one focus.

　　Kepler’s Second Law

　　If a line is drawn from the sun to the planet, then the area swept out by this line in a given time interval is constant.

　　Kepler’s Third Law

　　Given the period, T, and semimajor axis, a, of a planet’s orbit, the ratio is the same for every planet.

　　Kinematic equations

　　The five equations used to solve problems in kinematics in one dimension with uniform acceleration.

　　Kinematics

　　Kinematics is the study and description of the motion of objects.

　　Kinetic energy

　　Energy associated with the state of motion. The translational kinetic energy of an object is given by the equation .

　　Kinetic friction

　　The force between two surfaces moving relative to one another. The frictional force is parallel to the plane of contact between the two objects and in the opposite direction of the sliding object’s motion.

　　Kinetic theory of gases

　　A rough approximation of how gases work, that is quite accurate in everyday conditions. According to the kinetic theory, gases are made up of tiny, round molecules that move about in accordance with Newton’s Laws, and collide with one another and other objects elastically. We can derive the ideal gas law from the kinetic theory.