1. Unit 5 Key Terms
1-Be able to determine the effects of loading in static engineering
systems
Interactions: Interactions occur between bodies that are in contact and between the earth and a
body.
Force: Force is not visible but its effect is visible. Force is rate of change of momentum.
Momentum is product of mass and velocity.
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Line of action: the direction the force is acting
Point of application - where precisely the force is exerted
Direction - information on its line of action (e.g., could be vertical, or horizontal, or at some
angle) or
Sense - for a given direction, which of the two opposite possibilities; e.g. upward vs. downwards,
or leftward vs. rightward.
Magnitude - intensity of the force represented with a label (and sometimes by the length of the
arrow), and measured in Newtons.
A concentrated load is a force applied at a single poi will produce equilibrium on a beam or
structure
A distributed load is spread out over a large area.
Equilibrant: the force that when applied to a system of forces.
Resultant: the force that represents the combined effect of a force system.
Moment: the tendency of a force to rotate the object on which it acts.
Pythagoras’s theorem: the square of the hypotenuse of a right-angled triangle is equal to the
sum of the squares on the other side.
Modulus of elasticity, an object or substance's tendency to be deformed elastically (i.e., non-permanently)
when a force is applied to it.
Modulus of Rigidity (or Shear Modulus) is the coefficient of elasticity for a shearing force.
Stress is the ratio of applied force F (Tensile force or Compressive force) and cross section A,
defined as "force per area".
Strain. is defined as extension per unit length. Strain has no units because it is a ratio of lengths.
Shear Stress: Stress parallel to the plane
Sheer Strain is defined as "deformation of a solid due to stress"
Factor of safety: how much stronger the system is than it usually needs to be for an intended
load.

2. Unit 5 Key Terms
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2-Be able to determine work, power and energy transfer in dynamic
engineering systems.
Displacement: 1-the action of moving something from its place or position.
2-the occupation by a submerged body or part of a body of a volume which would otherwise be
occupied by a fluid
Linear motion: is motion along a straight line.
Acceleration: The acceleration of an object is its change in velocity per unit time in the direction
of change. It is a vector with direction and magnitude. Unit is m /sec.2
Velocity: The velocy of an object is its displacement per unit time. In the direction of
displacement. It has a direction and a magnitude
Initial velocity: The velocity of anything at the beginning of a specific phase of its motion.
Final velocity: velocity at the final point of time.
The mass of an object refers to the amount of matter that is contained by the object;
The weight of an object is the force of gravity acting upon that object.
Kinetic Energy: Energy possessed by an object by virtue of its motion.
Potential energy is the stored energy of position.
3-Be able to determine the parameters of fluid systems
Pressure: It is the normal (perpendicular) force acting on unit area
Hydrostatic pressure: The pressure exerted by a fluid at equilibrium at a given point within the
fluid, due to the force of gravity.
Hydrostatic thrust a normal force exerted on anypart of a solid surface which is on contact witha
fluid.
Centroid: the centre of area of a plane shape.
Specific Volume: It is inverse of density. It is volume per unit weight.
Volume flow rate: the flow of volume of fluid through a surface per unit time.
Mass flow rate: the mass of a substance which passes through a given surface per unit of time.
Upthrust: the apparent loss in weight of a body immersed in a liquid is equal to the weight of the
displaced fluid
Density: It is mass per unit volume

3. Unit 5 Key Terms
4 Be able to determine the effects of energy transfer in
thermodynamic systems
Thermodynamics the principle that at constant temperature the internal energy of an ideal gas is
independent of volume. Real gases change their internal energy with volume as a result of
intermolecular forces
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Heat: It is a form of energy. Its unit is Calorie.
Temperature: Temperature is measure of heat energy level whereas heat is a measure of total
internal energy contained in a body
Latent heat: Latent heat is related to changes in phase between liquids, gases, and solids
Sensible heat is related to changes in temperature of a gas or object with no change in phase.
Phase change: change from one state (solid or liquid or gas) to another without a change in
chemical composition.
Thermal efficiency: the efficiency of a heat engine measured by the ratio of the work done by it
to the heat supplied to it.
Thermal expansion is the tendency of matter to change in volume in response to a change in
temperature through heat transfer.
Superheated steam: a colourless (dry) gas a temperature above the boiling point of water.
Energy value: the amount of potential energy of a specified amount of fuel that is released as
heat when fuel is combusted.
Potential energy: the stored energy of position possessed by an object.