Kelvin's statement of second law of thermodynamics:  It is impossible that, at the end of a cycle of changes, heat has been extracted from a reservoir and an equal amount of work has been produced without producing some other effect. 
Kinetic energy:  The energy possessed by a body due to its motion, it is equal to ½ mv2, where m is the mass and v is the speed of the body 
Kepler's first law of planetary motion:  Each planet moves in an elliptical orbit, with the sun located at one of the foci. 
Kepler's second law of planetary motion:  The radius vector joining the planet to the sun covers equal areas in equal intervals of time. 
Kepler's third law of planetary motion:  The square of the period of a planet is directly proportional to the cube of the radius of the semi major axis of the orbit. 
Kilocalorie:  The amount of energy required to raise the temperature of one kilogram of water by 1 , 1 Kcal = 1000 calories. 
