# Physics WJEC: Ph1 Key words Flash cards

• Fun physics flash cards on key words of the of PH1 WJEC.
• Not for the faint of heart.
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Scalar
a quantity that has a mangnitude only i.e. Speed.
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Vector
a quantity that has magnitude and direction i.e. Velocity
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Force (be with you always)
a push or a pull acting on a body from some external body.
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Resultant Force
the vector sum of forces acting on a body (sometimes the resultant force is callen the net force.)
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Resolving Vectors
finding vectors (the so-called Components) in specific directions, which add together vectorially to make the original vector, and so, together, are equivilent to this vector. (i.e The Horizontal and Vertical components of a vector)
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Newtons third law
If a body A exerts a force on body B, then B exerts an equal and opposite force on A.
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Free body diagram
a simplified representation of the body along with arrows showing the forces acting on the body.
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Density (definition is equation + Units)
Mass/Volume Unit: Kg m¯³ (The mass and volume apply to any sample of the material)
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=Force x Perpendicular distance from the axis.
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Principle of moments
For a system in equilibrium the resultant moment = 0
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Center of Gravity
the point where the entire weight of the body is considered to act.
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Displacement
the displacement of a point B from a point A is the shortest distance from A to B together with the direction.
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Mean speed (Equation for definition)
= Total distance travelled/Total time taken (OR the total distance Divided by the change in time)
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Mean Velocity (Equation for definition)
=Total displacement/Total time taken (OR change in displacement divided by the change in time) (in graphical representation the direction will usually be represented as a "+" or a "-")
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Mean acceleration (Equation for definition)
Change in Velocity/total time taken
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Instantaneous Speed
rate of change of distance
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Instantaneous Velocity
rate of change of displacement
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Instantaneous Acceleration
rate of change of Velocity
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Work (equation for explaination)
=Force multiplied by the distance moved in the direction of the force. (i.e. W= Fxcosθ) (the "x" in this case means Distance traveled)
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Energy
The ability to do work
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Power
Rate of energy transfer [OR the rate of work done] i.e (∆Work done / ∆Time ) { ∆ = the change in... }
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Principle of conservation of energy
Energy cannot be created or destroyed only transfered from one form to another
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Static Electricity
movement of charges due to rubbing of insulators (different from constant charge flows from cells, ETC.)
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Current (include equation)
Rate of flo9w of charge = ∆Q / ∆t (Q= Charge ∆= Change in.. t=time)
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Drift velocity
the small average speed of electrons in a conductor due to an applied PD. (PD= Potential difference [AKA. Voltage]
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n (in drift velocity equation)
the number of free electrons per cubic metre.
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Potential difference (pd) between two points
the energy converted from electrical potential energy to some other form per coulomb of charge flowing from one point to the other. *unit= J C¯¹
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The resistance of a conductor
the pd (v) placed across it divided by the resulting current (I) through it. R= V/I (R= resistance, V= PD (or voltage), I= Current) *unit: Ohm (Ω) [= V A¯¹ ]
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Ohm's law
the current flowing through a metal wire at constant tempurature is proportional to the pd (Voltage) across it.
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Superconductor
a conductor with zero resistance at a specific tempurature (usually when cooled to liquid helium or liquid Nitrogen tempuratures)
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Superconducting transition tempurature
the tempurature at which a material, when cooled, suddenly, looses all it's resistance and becomes a superconductor.
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EMF
the energy converted from some form (usually chemical [in power supplies]) to electrical potential energy per coulomb of charge flowing through the source. *unit= V
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## Other cards in this set

### Card 2

#### Front

a quantity that has magnitude and direction i.e. Velocity

Vector

### Card 3

#### Front

a push or a pull acting on a body from some external body.

### Card 4

#### Front

the vector sum of forces acting on a body (sometimes the resultant force is callen the net force.)

### Card 5

#### Front

finding vectors (the so-called Components) in specific directions, which add together vectorially to make the original vector, and so, together, are equivilent to this vector. (i.e The Horizontal and Vertical components of a vector)