Power Engineering 4th Class - Unit A4
Review Questions With Complete Solutions
Velocity (m/s) - Answer-Change in position / time
Acceleration (m/s^2) - Answer-Change in velocity (m/s) / time (s)
Force (Newton) - Answer-mass (kg) x acceleration (m/s^2) , any action on a body
that tends to change its size, shape, or its state of rest or motion
Force of Gravity - Answer-mass (kg) x 9.81 m/s^2
Pressure (Pa) - Answer-Force (N) / area (m^2)
Space Diagram - Answer-Illustrates a system of vectors
Co-planar Vectors - Answer-Vectors that are all in the same plane
Concurrent Vectors - Answer-Vectors whose lines of action meet at one point
Resultant - Answer-A vector that represents the sum of two or more vectors
,Absolute Pressure - Answer-Atmospheric pressure + gauge pressure
Static Friction - Answer-A friction force that acts on objects that are not moving.
Always greater than kinetic friction
Kinetic Friction - Answer-Friction that opposes motion once the motion has
already started. Not affected by speed of body Always greater than rolling
friction.
Rolling Friction - Answer-The friction force that acts on rolling objects, Always less
than kinetic friction
Fluid Friction - Answer-Friction that occurs as an object moves through a fluid
Force of Friction - Answer-Force that resists motion when two materials are in
contact. Proportional to the force that presses the two surfaces together. Not
affected by area. Affected by roughness.
Elasticity - Answer-The ability of a material to return to its original shape after
being disturbed
Stiffness - Answer-Ability of a material to resist a change in shape or size when a
load is applied
Plasticity - Answer-Ability of a material to retain its deformed shape when a
deforming force is removed
,Ductility - Answer-Ability of a material to be stretched and reduced in cross
section without breaking
Toughness - Answer-Ability of a material to absorb energy before breaking
Hardness - Answer-Ability of a material to resist penetration
Stress - Answer-Internal resistance to an external load , Equal to Load (N) / Area
(m^2)
Tensile Stress - Answer-Forces that act at opposite ends of a bar and pull away
from each other, creating tension on the bar
Compressive Stress - Answer-A stress due to a force pushing together on a body
Shear Stress - Answer-Forces on a bar that act parallel to another but are not on
the same plane
Ultimate Stress - Answer-The stress at which fracture of the material occurs
Allowable Stress - Answer-The greatest stress which a material is capable of
developing without permanent deformation remaining upon the complete
release of stress.
Elastic Limit - Answer-Maximum stress that a material will withstand without
permanent deformation. Will return to its original size and shape
, Factor of Safety - Answer-Ultimate Stress / Allowable Stress
Strain - Answer-A measure of the deformation produced in a member by a load ,
Equal to Change in Length (l) / Original Length (L)
Circumferance - Answer-pi x Diameter
Linear Speed - Answer-Equal to rev/min x pi D / 60
Four States of Matter - Answer-solid, liquid, gas, plasma
Phase - Answer-One individual substance in one particular state
Chemical Properties - Answer-Only observed when there is a chemical change or
reaction , Examples are Heat of combustion, Toxicity, Flammability, Chemical
Stability
Physical Properties - Answer-Characteristics that you can observe without a
change in the composition of matter
Intensive Physical Property - Answer-Not dependent on the amount of matter
Extensive Physical Property - Answer-Dependent on the amount of matter
Review Questions With Complete Solutions
Velocity (m/s) - Answer-Change in position / time
Acceleration (m/s^2) - Answer-Change in velocity (m/s) / time (s)
Force (Newton) - Answer-mass (kg) x acceleration (m/s^2) , any action on a body
that tends to change its size, shape, or its state of rest or motion
Force of Gravity - Answer-mass (kg) x 9.81 m/s^2
Pressure (Pa) - Answer-Force (N) / area (m^2)
Space Diagram - Answer-Illustrates a system of vectors
Co-planar Vectors - Answer-Vectors that are all in the same plane
Concurrent Vectors - Answer-Vectors whose lines of action meet at one point
Resultant - Answer-A vector that represents the sum of two or more vectors
,Absolute Pressure - Answer-Atmospheric pressure + gauge pressure
Static Friction - Answer-A friction force that acts on objects that are not moving.
Always greater than kinetic friction
Kinetic Friction - Answer-Friction that opposes motion once the motion has
already started. Not affected by speed of body Always greater than rolling
friction.
Rolling Friction - Answer-The friction force that acts on rolling objects, Always less
than kinetic friction
Fluid Friction - Answer-Friction that occurs as an object moves through a fluid
Force of Friction - Answer-Force that resists motion when two materials are in
contact. Proportional to the force that presses the two surfaces together. Not
affected by area. Affected by roughness.
Elasticity - Answer-The ability of a material to return to its original shape after
being disturbed
Stiffness - Answer-Ability of a material to resist a change in shape or size when a
load is applied
Plasticity - Answer-Ability of a material to retain its deformed shape when a
deforming force is removed
,Ductility - Answer-Ability of a material to be stretched and reduced in cross
section without breaking
Toughness - Answer-Ability of a material to absorb energy before breaking
Hardness - Answer-Ability of a material to resist penetration
Stress - Answer-Internal resistance to an external load , Equal to Load (N) / Area
(m^2)
Tensile Stress - Answer-Forces that act at opposite ends of a bar and pull away
from each other, creating tension on the bar
Compressive Stress - Answer-A stress due to a force pushing together on a body
Shear Stress - Answer-Forces on a bar that act parallel to another but are not on
the same plane
Ultimate Stress - Answer-The stress at which fracture of the material occurs
Allowable Stress - Answer-The greatest stress which a material is capable of
developing without permanent deformation remaining upon the complete
release of stress.
Elastic Limit - Answer-Maximum stress that a material will withstand without
permanent deformation. Will return to its original size and shape
, Factor of Safety - Answer-Ultimate Stress / Allowable Stress
Strain - Answer-A measure of the deformation produced in a member by a load ,
Equal to Change in Length (l) / Original Length (L)
Circumferance - Answer-pi x Diameter
Linear Speed - Answer-Equal to rev/min x pi D / 60
Four States of Matter - Answer-solid, liquid, gas, plasma
Phase - Answer-One individual substance in one particular state
Chemical Properties - Answer-Only observed when there is a chemical change or
reaction , Examples are Heat of combustion, Toxicity, Flammability, Chemical
Stability
Physical Properties - Answer-Characteristics that you can observe without a
change in the composition of matter
Intensive Physical Property - Answer-Not dependent on the amount of matter
Extensive Physical Property - Answer-Dependent on the amount of matter
