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