# Physics Calculations

**Averaging**- In any process it is often necessary to average a number of measurements to gain any confidence in the measured value.
**Conical Pendulum**- The motion of the wire from which the bob hangs describes the surface of a cone.
**Equations of Motion**- There are four basic equations that describe the motion of a body moving with constant acceleration.
**Frequency**- The rate of repetition of periodic motion measured in hertz (cycles per second).
**Froude Number**- A dimensionless number used in the study of fluid flow problems with models.
**Gravitational Potential**- The worrk done in bringing a unit mass from infinity to that point. The assumption being that the gravitational potential is zero at infinity.
**Gravitational Potential Energy**- The work done by the force of gravity when an object falls from a particular point in space to the location assigned the value of zero.
**Julian Day**- Instituted by J. Julius Scaliger in 1582. The Julian date is independent of various calendars and chronological events.
**Length Contraction**- An observer in motion relative to an object measures the length of that object along the direction of motion to be contracted when compared to the length measured by an observer at rest relative to the object.
**Mach Number**- The ratio of the speed of a body or flow of a fluid to the local speed of sound in the fluid.
**Moments of Inertia**- Principal axes for bodies of uniform density.
**Newton′s Law of Universal Gravitation***Every particle in the Universe attracts every other with a force which is proportional to the product of their masses and inversely proportional to the square of their seperation.***Ohm**- Defined as the resistance of a conductor through which a current of one ampere is flowing when the potential difference across it is one volt.
**Pendulums**- There are a number of different forms of pendulum. The main characteristic being that when the mass is displaced from it's position of rest it will oscillate at a fixed frequency.
**Prandtl Number**- A dimensionless group often used in heat exchange calculations.
**Relativistic Kinetic Energy**- The energy that a body possesses solely because it is moving.
**Resistance**- The electrical resistance of a conductor.
**Reynolds Number**- This is a non-dimensional number (consistent units) which describes whether fluid flow is laminar, turbulent, or transitional between the two.
**Simple Pendulum**- The mass hung on a fine wire, displaced from rest and released.
**Snells Law**- Snells law defines the angle of refraction of a light beam when it passes from one medium to another.
**Speed of Sound**- Depends on the elastic and inertial properties of the particular medium.
**Strouhal Number**- A dimensionless unit.
**Thin Rod**- The moment of inertia of a thin rod.
**Wavelength**- The shortest repetition length for a periodic wave.
**Wavenumber**- Wavenumber describes the spatial variation of waves, phase change per unit distance.
**Wheel**- The Mesopotamians are credited with the invention of the wheel.

**Subjects: ** Physics