4th Class Power Engineering Part A
Exam Questions and Answers Graded A+
Velocity (m/s) - Correct answer-Change in position / time
Acceleration (m/s^2) - Correct answer-Change in velocity (m/s) / time (s)
Force (Newton) - Correct 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 - Correct answer-mass (kg) x 9.81 m/s^2
Pressure (Pa) - Correct answer-Force (N) / area (m^2)
Work (J) - Correct answer-Force (N) x distance (m)
Power - Correct answer-Work done / time , Rate of doing work
Potential Energy (J) - Correct answer-mass x gravity x height , the ability of a body
to do work due by virtue of its position
Kinetic Energy (J) - Correct answer-1/2 x mass x velocity^2 , The ability of a body
to do work due to its motion
Energy (J) - Correct answer-The capacity of a body to do work
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,Tonne - Correct answer-1000 kilograms
Moment of Force (Nm) - Correct answer-Force (N) x Distance (m) , A force, acting
on a body at any distance from a point on that body, will tend to produce rotation
around that point
Clockwise Moments - Correct answer-Equal to Counter-clockwise moments
Upward Forces - Correct answer-Equal to Downward forces
Actual Mechanical Advantage (Ma) - Correct answer-Load (N) / Effort (N)
Velocity Ratio (VR) - Correct answer-Distance moved by Effort / Distance moved
by Load
Efficiency - Correct answer-Output Work / Input Work
Output Work - Correct answer-Load x Distance moved by load
Input Work - Correct answer-Effort x Distance moved by effort , Equals Output
work + Wasted work
Ideal Mechanical Advantage (MA) - Correct answer-Equal to Velocity Ratio (VR)
Load x r - Correct answer-Equal to Effort x R
VR - Correct answer-Equal to R/r and D/d
Load /Effort - Correct answer-Equal to R/r
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,Scalar - Correct answer-A physical quantity that has magnitude but no direction
Vector - Correct answer-A quantity that has magnitude and direction
Space Diagram - Correct answer-Illustrates a system of vectors
Co-planar Vectors - Correct answer-Vectors that are all in the same plane
Concurrent Vectors - Correct answer-Vectors whose lines of action meet at one
point
Resultant - Correct answer-A vector that represents the sum of two or more vectors
Absolute Pressure - Correct answer-Atmospheric pressure + gauge pressure
Static Friction - Correct answer-A friction force that acts on objects that are not
moving. Always greater than kinetic friction
Kinetic Friction - Correct answer-Friction that opposes motion once the motion has
already started. Not affected by speed of body Always greater than rolling friction.
Rolling Friction - Correct answer-The friction force that acts on rolling objects,
Always less than kinetic friction
Fluid Friction - Correct answer-Friction that occurs as an object moves through a
fluid
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, Force of Friction - Correct 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 - Correct answer-The ability of a material to return to its original shape
after being disturbed
Stiffness - Correct answer-Ability of a material to resist a change in shape or size
when a load is applied
Plasticity - Correct answer-Ability of a material to retain its deformed shape when
a deforming force is removed
Ductility - Correct answer-Ability of a material to be stretched and reduced in
cross section without breaking
Toughness - Correct answer-Ability of a material to absorb energy before breaking
Hardness - Correct answer-Ability of a material to resist penetration
Stress - Correct answer-Internal resistance to an external load , Equal to Load (N) /
Area (m^2)
Tensile Stress - Correct answer-Forces that act at opposite ends of a bar and pull
away from each other, creating tension on the bar
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Exam Questions and Answers Graded A+
Velocity (m/s) - Correct answer-Change in position / time
Acceleration (m/s^2) - Correct answer-Change in velocity (m/s) / time (s)
Force (Newton) - Correct 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 - Correct answer-mass (kg) x 9.81 m/s^2
Pressure (Pa) - Correct answer-Force (N) / area (m^2)
Work (J) - Correct answer-Force (N) x distance (m)
Power - Correct answer-Work done / time , Rate of doing work
Potential Energy (J) - Correct answer-mass x gravity x height , the ability of a body
to do work due by virtue of its position
Kinetic Energy (J) - Correct answer-1/2 x mass x velocity^2 , The ability of a body
to do work due to its motion
Energy (J) - Correct answer-The capacity of a body to do work
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,Tonne - Correct answer-1000 kilograms
Moment of Force (Nm) - Correct answer-Force (N) x Distance (m) , A force, acting
on a body at any distance from a point on that body, will tend to produce rotation
around that point
Clockwise Moments - Correct answer-Equal to Counter-clockwise moments
Upward Forces - Correct answer-Equal to Downward forces
Actual Mechanical Advantage (Ma) - Correct answer-Load (N) / Effort (N)
Velocity Ratio (VR) - Correct answer-Distance moved by Effort / Distance moved
by Load
Efficiency - Correct answer-Output Work / Input Work
Output Work - Correct answer-Load x Distance moved by load
Input Work - Correct answer-Effort x Distance moved by effort , Equals Output
work + Wasted work
Ideal Mechanical Advantage (MA) - Correct answer-Equal to Velocity Ratio (VR)
Load x r - Correct answer-Equal to Effort x R
VR - Correct answer-Equal to R/r and D/d
Load /Effort - Correct answer-Equal to R/r
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,Scalar - Correct answer-A physical quantity that has magnitude but no direction
Vector - Correct answer-A quantity that has magnitude and direction
Space Diagram - Correct answer-Illustrates a system of vectors
Co-planar Vectors - Correct answer-Vectors that are all in the same plane
Concurrent Vectors - Correct answer-Vectors whose lines of action meet at one
point
Resultant - Correct answer-A vector that represents the sum of two or more vectors
Absolute Pressure - Correct answer-Atmospheric pressure + gauge pressure
Static Friction - Correct answer-A friction force that acts on objects that are not
moving. Always greater than kinetic friction
Kinetic Friction - Correct answer-Friction that opposes motion once the motion has
already started. Not affected by speed of body Always greater than rolling friction.
Rolling Friction - Correct answer-The friction force that acts on rolling objects,
Always less than kinetic friction
Fluid Friction - Correct answer-Friction that occurs as an object moves through a
fluid
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, Force of Friction - Correct 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 - Correct answer-The ability of a material to return to its original shape
after being disturbed
Stiffness - Correct answer-Ability of a material to resist a change in shape or size
when a load is applied
Plasticity - Correct answer-Ability of a material to retain its deformed shape when
a deforming force is removed
Ductility - Correct answer-Ability of a material to be stretched and reduced in
cross section without breaking
Toughness - Correct answer-Ability of a material to absorb energy before breaking
Hardness - Correct answer-Ability of a material to resist penetration
Stress - Correct answer-Internal resistance to an external load , Equal to Load (N) /
Area (m^2)
Tensile Stress - Correct answer-Forces that act at opposite ends of a bar and pull
away from each other, creating tension on the bar
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