4th Class Power Engineering Part A Exam Questions With 100% Answers

4th Class Power Engineering Part A Exam Questions With 100% Answers Velocity (m/s) - answerChange in position / time Acceleration (m/s^2) - answerChange in velocity (m/s) / time (s) Force (Newton) - answermass (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 - answermass (kg) x 9.81 m/s^2 Pressure (Pa) - answerForce (N) / area (m^2) Work (J) - answerForce (N) x distance (m) Power - answerWork done / time , Rate of doing work Potential Energy (J) - answermass x gravity x height , the ability of a body to do work due by virtue of its position Kinetic Energy (J) - answer1/2 x mass x velocity^2 , The ability of a body to do work due to its motion Energy (J) - answerThe capacity of a body to do work Tonne - answer1000 kilograms Moment of Force (Nm) - answerForce (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 - answerEqual to Counter-clockwise moments Upward Forces - answerEqual to Downward forces Actual Mechanical Advantage (Ma) - answerLoad (N) / Effort (N) Velocity Ratio (VR) - answerDistance moved by Effort / Distance moved by Load Efficiency - answerOutput Work / Input Work Output Work - answerLoad x Distance moved by load Input Work - answerEffort x Distance moved by effort , Equals Output work + Wasted work Ideal Mechanical Advantage (MA) - answerEqual to Velocity Ratio (VR) Load x r - answerEqual to Effort x R VR - answerEqual to R/r and D/d Load /Effort - answerEqual to R/r Scalar - answerA physical quantity that has magnitude but no direction Vector - answerA quantity that has magnitude and direction Space Diagram - answerIllustrates a system of vectors Co-planar Vectors - answerVectors that are all in the same plane Concurrent Vectors - answerVectors whose lines of action meet at one point Resultant - answerA vector that represents the sum of two or more vectors Absolute Pressure - answerAtmospheric pressure + gauge pressure Static Friction - answerA friction force that acts on objects that are not moving. Always greater than kinetic friction Kinetic Friction - answerFriction that opposes motion once the motion has already started. Not affected by speed of body Always greater than rolling friction. Rolling Friction - answerThe friction force that acts on rolling objects, Always less than kinetic friction Fluid Friction - answerFriction that occurs as an object moves through a fluid Force of Friction - answerForce 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 - answerThe ability of a material to return to its original shape after being disturbed Stiffness - answerAbility of a material to resist a change in shape or size when a load is applied Plasticity - answerAbility of a material to retain its deformed shape when a deforming force is removed Ductility - answerAbility of a material to be stretched and reduced in cross section without breaking Toughness - answerAbility of a material to absorb energy before breaking Hardness - answerAbility of a material to resist penetration Stress - answerInternal resistance to an external load , Equal to Load (N) / Area (m^2) Tensile Stress - answerForces that act at opposite ends of a bar and pull away from each other, creating tension on the bar Compressive Stress - answerA stress due to a force pushing together on a body Shear Stress - answerForces on a bar that act parallel to another but are not on the same plane Ultimate Stress - answerThe stress at which fracture of the material occurs Allowable Stress - answerThe greatest stress which a material is capable of developing without permanent deformation remaining upon the complete release of stress. Elastic Limit - answerMaximum stress that a material will withstand without permanent deformation. Will return to its original size and shape Factor of Safety - answerUltimate Stress / Allowable Stress Strain - answerA measure of the deformation produced in a member by a load , Equal to Change in Length (l) / Original Length (L) Circumferance - answerpi x Diameter Linear Speed - answerEqual to rev/min x pi D / 60 Four States of Matter - answersolid, liquid, gas, plasma Phase - answerOne individual substance in one particular state Chemical Properties - answerOnly observed when there is a chemical change or reaction , Examples are Heat of combustion, Toxicity, Flammability, Chemical Stability Physical Properties - answerCharacteristics that you can observe without a change in the composition of matter Intensive Physical Property - answerNot dependent on the amount of matter Extensive Physical Property - answerDependent on the amount of matter