Science Fair Project Encyclopedia
List of physical quantities
List of physical quantities
Note that the dimensions chosen as the primary dimensions is arbitrary and dependent upon the choice of units used. The dimensional analysis here is based on the base units of the International System of Units. Other dimensions such as force [F] rather than mass [M], or charge [Q] rather than current [I], could be used. Even the number of dimensions used is not a fixed, invariable number. In a three-base unit cgs system, for example, the units of charge are erg½ cm½ and the dimensional analysis of this quantity in terms of the quantities represented by the base units is [M]½ [L] [T]-1, whereas in the analysis below charge has units of [I] [T]. Also note that the symbols are not International Standards and may be used differently than shown here. However, these symbols are often used in the science community.
| Base Physical Quantity | Symbol | Meaning | Dimensions in SI | SI unit |
| Length | l | The one dimensional extent of an object | L | metre (m) |
| Mass | m | The amount of matter in an object | M | kilogram (kg) |
| Time | t | The duration of an event | T | second (s) |
| Current | I | The rate of flow of electrical charge | I | ampere (A) |
| Temperature | T | . | Θ | kelvin (K) |
| Amount of substance | n | Number of particles compared to number of atoms in 0.012 kg C12 | ... | mol (mol) |
| Luminous intensity | L | ... | candela (cd) | |
| Derived Physical Quantity | Symbol | Meaning | Dimensions | SI unit |
| Area | A | The two dimensional extent of an object | L2 | square metre |
| Angle | θ | . | one | radian (rad) |
| Solid angle | . | . | one | steradian (sr) |
| Volume | V | The three dimensional extent of an object | L3 | cubic metre |
| Linear density | ρl | The amount of mass per unit length of a 1-dimensional object | M L-1 | kilogram per metre |
| Area density | ρA | The amount of mass per unit area of a 2-dimensional object | M L-2 | kilogram per square metre |
| (Volume) Density | ρ | The amount of mass per unit volume of a 3-dimensional object | M L-3 | kilogram per cubic metre |
| Speed | v | The rate of change of position of an object | L T-1 | metre per second |
| Acceleration | a | The rate of change of speed of an object | L T-2 | metre per second squared |
| Momentum | p | The product of an object's mass and its velocity | M L T-1 | kilogram metre per second or newton second |
| Impulse | p | The product of a force and the time over which it acts | M L T-1 | kilogram metre per second or newton second |
| Force | F | That which causes or tends to cause acceleration in an object with mass | M L T-2 | newton = kilogram metre per second squared |
| Work | W | The energy dissipated by a force moving through a distance, and calculated from the product of the force and the distance moved in the direction of the force | M L2 T-2 | joule = newton metre |
| Energy | E | The capacity of a body or system to do work | M L2 T-2 | joule = newton metre |
| Kinetic energy | Ek | The energy that a body possesses by virtue of its speed or velocity | M L2 T-2 | joule = newton metre |
| Potential energy | Ep | The energy that a body possesses by virtue of its position in a potential field | M L2 T-2 | joule = newton metre |
| Power | P | The rate of change of energy over time | M L2 T-3 | watt = joule per second |
| Pressure | p | The amount of force per unit area | M L-1 T-2 | pascal = newton per square metre |
| Electric Charge | Q | . | I T | coulomb = ampere second |
| Moment | . | . | ? | . |
| Torque | T | . | M L2 T-2 | newton metre |
| Phase angle | . | . | one | radian |
| Wavelength | λ | . | L | metre |
| Frequency | f | . | T-1 | hertz |
| Angular speed | . | . | T-1 | radian per second |
| Angular velocity | . | . | T-1 | radian per second |
| Angular acceleration | . | . | T-2 | radian per second squared |
| Moment of inertia | I | . | M L2 | kilogram metre squared |
| Area moment of inertia | . | . | L4 | |
| Angular momentum | . | . | ? | . |
| Rotational energy or Angular kinetic energy | . | . | ? | . |
| Magnetic flux | . | measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field | M T-2 I-1 | tesla |
Some further Physical Quantities yet to be incorporated into the above table
(list incomplete)
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