PH1 physics definitions

If body A exerts a force on body B, then body B exerts an equal and opposite force on A

Force x perpendicular distance from the axis.

For a system in equilibrium, the resultant moment = 0

The point where the entire weight of the body is considered to act.

The displacement of a point B from a point A is the shortest distance from A to B together with the direction

The ability to do work

Energy cannot be created or destroyed, only transferred from one form to another.

The small average speed of electrons in a conductor due to an applied pd.

The number of free electrons per cubic metre

• The energy converted from electrical potential energy to some other form per coulomb of charge flowing from one point to another.
• Unit = JC-¹

The pd placed across it divided by the resulting current through it.

The current flowing though a metal wire is proportional to the pd flowing across it provided temperature is constant.

• The e.m.f. of a source is the energy converted from some
• other form (e.g. chemical) to electrical potential energy per coulomb of charge
• flowing through the source.

• Unit:
• V.

A conductor with zero resistance

The temperature at which a material when cooled suddenly, loses all its electrical resistance and becomes a superconductor.