SL PHYSICS VOICE

  Displacement The shortest distance between two places and there must be a direction. According to Newton's first low of motion, any object is rest or moving at constant velocity, if there is no resultant force on that object. A force exerted on the body has two effects;   External effect - (change of motion, resisting force) Internal effect - (tendency of the body to deform causes developing stain, stresses. Equilibrium of force Vector sum of the all external forces acting on the body must be zero. The sum of external torques must be zero about any point. Moment Moment = Fd SI units - Nm Couple Moment A couple should consist of two parallel forces that are equal in magnitude and opposite in direction. must not share same line of action. It does not produce any translation, only rotation. Moment of the couple about any point is always a constant. Center of Gravity The center of gravity of a body is the single point at which the entire weight of the body can be considered...

  MATTER OCCUPIES SPACE AND HAS A MASS THE CHEMICAL ELEMENTS A chemical element is a pure substance that cannot be divided or changed into different substances by ordinary chemical methods. STRUCTURE OF ATOMS An atom defined as the smallest part of a chemical element that retains the identity of the element. Around the nucleus, small charged particles called electrons move in complicated patterns called orbitals . The outer-most orbitals shell of any atom's electrons is called the valence shell . The number of electrons in the valence shell determines the chemical bonding properties of the material as well as other characteristics such as conductivity . Two or more substances may share the electrons in their valence shell and form a covalent  bond . ISOTOPES When atoms of the same element have different number of neutrons, they are called isotopes. Same in chemically Different in physically (because of different mass) MOLECULES Molecules is the smallest structural unit of...