Forces Can Act Without Touching Force Fields O

Forces Can Act Without Touching

Force Fields O When a force acts at a distance, the area in which an object experiences a force is called a field.

Types of Non-contact Forces OGravitational OElectrical OMagnetic

Gravitational Force O Gravity-Force of attraction between two objects due to mass. O Attractive force (pulls objects together) O The strength of the force is determined by the masses involved and the distance between them.

Factors that Affect Gravitational Pull OMass- Objects with greater mass have more attraction than objects with less mass. ODistance- Objects far apart have a weaker attraction than objects that are close together.

Difference Between Mass and Weight O Weight- Force of attraction due to gravity. O Can change due to the amount of gravitational pull. O An increase in gravitation pull will increase the weight on an object.

OMass- The amount of matter in an object. OWill not change unless you add matter or take it away. It is not affected by gravity. O http: //www. youtube. com/watch? v=wuml. TLUg. Pp. E

Electrical Force O Occurs when two charged objects exert a force on each other. O Charge- property that leads to electromagnetic interactions. O Protons- positive charge. O Neutrons-no charge. O Electrons-negative charge.

Factors that Affect Electric Force O Charge- The type of charge will determine if the objects attract (pull) or repel (push). O Unlike (opposite) charges attract. O Like (same) charges repel. O The amount of charge on each object affects the strength. (increase in charge=an increase in force)

Types of Charges

Factors That Affect Electric Force Cont. ODistance- the distance between object effects the electric force. OIncrease in distance= a decrease in force ODecrease in distance= an increase in force

Three Methods for Charging Objects O Friction-two objects rubbed together causing a transfer of electrons between objects. O Contact- a charged object and an uncharge object touch, and the charged object transfers its charge. O Induction- rearranging charges within an object without touching.

Materials That Affect Flow of Charge O Conductors- material that allows charges to move freely. O Ex. Copper and many metals. O Insulators- material in which charges can not flow freely. O Ex. Glass, rubber, plastic O Semiconductors- control the flow of charge O Ex. Silicon

Magnetic Force O Force that exerts from spinning electric charges. O Can attract or repel objects made of iron, nickle, cobalt, or a mixtures of these metals. O Like poles repel O Opposite poles attract

Factors that affect Magnetism O Distance- The greater the distance from the poles the weaker the magnetic field. O The closer the distance to the poles the stronger the magnetic field.

Causes of Magnetism O Type of atom- As electrons move in an atom it makes a magnetic field. When the amount of magnetic fields are the same, the object is not magnetized. When the amount of magnetic field are different, the object is magnetized.

O Formation of domains- groups of atoms form tiny areas with north and south poles. O When the north and south poles in the domains line up, the object makes a magnetic field.

Types of Magnets O Ferromagnets- material that can be turned into a magnet. (permanent magnets) O Ex. Iron, nickel and cobolt O Electromagnets- electric current produces a magnetic field. O Temporary Magnets- material whose domains temporarily line up after being rubbed with a magnet.

http: //www. youtube. com/watch? v=QCaa hq. DZr. AU