Physics Mechanics & Materials Vocabulary

acceleration

the vector defined as the rate of change of velocity

Archimedes’ Principle

The upthrust on an object is equal to the weight of fluid displaced

Average Speed

Speed for a whole journey, calculated by dividing the total distance for a journey by the total time for the journey

Centre Of Gravity

The point through which the weight of an object appears to act

compression

a force acting within a material in a direction that would squash the material. Also, decrease in size of a material sample under a compressive force

Conservation of Energy

The rule that requires that energy can never be created or destroyed

Conservation of linear momentum

The vector sum of the momenta of all objects in a system is the same before and after any collision between objects

Deformation

The process of alteration of form or shape

Density

A measure of the mass per unit volume of a substance

Displacement

The vector measurement of distance in a certain direction

Effciency

The ability of a machine to transfer energy usefully

Elastic limit

The maximum extension or compression that a material can undergo and still return to its original dimensions when the force is removed

Equilibrium

The situation for a body where there is zero resultant force and zero resultant moment. It will have zero acceleration

Explosion

A situation in which a stationary object separates into component parts, which move off at different velocities. Momentum must be conserved in explosions

Extension

An increase in size of a material sample caused by a tension force

Fluid

Any substance that can flow (liquid & Gases)

Gradient

The slope of a line or surface

GPE

The energy of an object stores by its virtue of its position in a gravitational field

Hysteresis

Where the extension under a certain load will be different depending on its history of past loads and extentions

Instantaneous Speed

The speed at any particular instant in time on a journey

Kinematics

The study of the description of the motion of objects

Kinetic Energy

KE=1/2mv²

Laminar Flow/Streamline Flow

A fluid moves with uniform lines in which the velocity is constant over tie

Limit of Proportionality

The maximum extension (or strain) that an object (or sample) can have, which is still proportional to the load (or stress) applied

Resultant force

The total force acting on a body

Scalar

A quantity that has magnitude only

Speed

The rate of change of distance

Spring Constant

The Hooke’s law constant of proportionality, k, for a spring under tension

strain

A proportionate measure of the extension(or compression) of a sample

Momentum

p=mv

Newton’s First Law of Motion

An object will remain at rest, or in a state of uniform motion until acted upon by resultant force

Newton’s Second Law of Motion

If an object’s mas is constant, the resultant force needed to cause an acceleration

Newton’s Third Law of Motion

For every actions. there is an equal and opposite reaction

Power

The rate of energy transfer

Principle of moments

A body will be in equilibrium if the sum of clockwise moments acting on it is equal to the sum of the anticlockwise moments

Projectile

A moving object on which the only force of significance action is gravity. The trajectory

Streamlines

Lines of laminar flow in hich the velocity is constant over time

Stress

A proportionate measure of the force on a sample

Tension

A force action within a material in a direction that would extend the material

Terminal Velocity

The velocity of a falling object when its weight is balanced b the sum of the drag and upthrust acting on it

Turbulent force

Fluid velocity in a particular place changes over time, often in an unpredictable manner

Upthrust

An upwards force on an object caused by the object displacing fluid

Vector

A quantity that must have both magnitude and direction

Velcoity

The rate of change of displacement

Viscosity

How resistant a fluid is to flowing

Work Done

This the product of a force and the distance moved in the direction of the force

Young Modulus

The stiffness constant for a material, equal to the stress divided by its corresponding strain

Hydrometer

An instrument used to determine the density of a fluid