Plumbing science Flashcards
what is hdpe?
High density polythelene
Tensile strength
how well a material reacts to being pulled + stretched
Compressive strength
the maximum stress a material can sustain whilst being crushed.
Shear Strength
the ability to withstand stress caused by a pair of opposing forces acting along a parallel line through a material
Ductility
A mechanical property that describes by how much a solid material can be pulled, pushed, stretched and elongated
Malleability
For a material to be deformed by compressive strength without fracturing.
Charles law
As temperature goes up so too will the pressure and therefore volume. (directly proportional)
Capillary attraction
the process where any fluid can be drawn upwards through small gaps against the action of gravity.
Boyle Law
If the pressure is doubled the volume of gas is halved
Sensible Heat
Is any heat that causes a change in temperature without a change in state
Latent Heat
A change of state without a change in temperature
Velocity
the speed of an object in a particular direction
Acceleration
A measure of how quickly the velocity of something is changing
Acceleration due to gravity
this is the rate of change of velocity of an object due to the gravitational pull on the earth
Force
An influence apon an object, which if acting alone will cause the motion of an object to change
Pressure
The application of continuous force by one body on another that is touching compressing
Flow rate
An Amount of fluid that flows through a pipe or tube over a given time.
Dynamic pressure- “working pressure”
Presents of water while in motion
Atmospheric pressure
The amount of force or pressure exerted by the atmosphere on the earth and the objects located on it. Atm decreases with height
The Bernoulli effect
If a pipe is reduced in size then an increase in the speed of the fluid occurs simultaneously with a decrease in the pressure or a decrease in the fluids potential energy
Voltage
(potential difference) is the driving force that pushes current around, volts, v
Current
is the rate of flow of charge around a circuit (current will flow through a component if there is a voltage across a component, ampere)
Direct current
Always flows in the same direction, electrons flow from negative pole (-) towards the positive pole (+)
Resistance
Anything in the circuit which slows the flow down, Ohms
Series circuit
A circuit where there is only one path from the source through all the loads back to the source
Alternate current
Does not travel in a constant direction. In fact it reverses its direction of travel constantly and uniformly throughout the circuit 50 times a second.
Conduction
Occurs when heat travels through a substance therefore heat being transferred from one molecule to another
Parallel Circuit
A parallel circuit is one that has at least two independent paths in the circuit
Convection
Is heat transfer through a fluid substance, such as water or air. (convection occurs because heated fluids (due to their lower density rise and cooled fluids fall)
Water
Maximum density of 1000kg at 4 Celsius (either raised or lowered density decreases, “Anomalous expansion”)
Power, Potential difference and Current (triangle)
Power = Watts
Potential difference = Volts
Current = Ampere
Potential difference, Current and Resistance
Potential difference = Volts
Current = Amperes
Resistance = Ohms
Force, pressure and area
Pressure = Force( divide ) Area
Pressure = N/M2 or Pascal (Pa)
Force= Newtons
Area= M2
What does PUWER cover?
The use of power tools and electrical equipment
What is HASAWA?
Heath and Safety at Work Act 1974
What is PUWER?
Provision and Use of Work Equipment Regulation 1998
What is PPE?
Personal Protective Equipment
What must an employer have if they have 5 or more employees?
A written health and safety policy
Does HASAWA just cover people at work?
No, It covers anyone that may be effected by work activities i.e. members of the public
