PE 3rd Class A1 Class Power Engineering - Sample Exam Questions And Answers

PE 3rd Class A1 Class Power Engineering - Sample Exam Questions And Answers 1. In a right angle triangle, the sine of an acute angle is equal to: Correct Answer: opposite side / hypotenuse If a right -angle triangle has an angle of 28O 37' and the hypotenuse is 120 mm, the length of the opposite side is: Correct Answer: 57.48 mm In the equation 0.004 + D = 0.0042, the valu e of D is: Correct Answer: 0.0002 As the cosine decreases, the Correct Answer: value of the angle increases Any two angles whose sum is 90° are: Correct Answer: complementary angles One is the trigonometric value of: Correct Answer: A. sine of 90° B. co sine of 0° C. tangent of 45° A automobile travels at 60 miles per hour. Expressed in metres per second, this would be equivalent to: Correct Answer: 26.81 m/s The force that is equal in magnitude but opposite in direction to the resultant force is calle d: Correct Answer: the equilibrant A scalar quantity is one which has only magnitude and can be fully described by: Correct Answer: a number with the necessary unit A body can be put into equilibrium by applying an additional force equal in magnitude but opposite in direction to the: Correct Answer: resultant A displacement of 9 m north of point A, and another of 6 m west of point A can be added to give a resultant d isplacement from point A of: Correct Answer: 10.8 m N of W The moment of a force about a point is: Correct Answer: a twisting or turning effect When the co -efficient of friction increases and the force between two surfaces remains constant, the friction force will: Correct Answer: increase A body having a gravitational force of 2000 N, is pulled along a horizontal surface at constant speed by a rope that makes an angle of 20° above the horizontal. If the pull on the rope is 150 N, the coefficient of slid ing friction is: Correct Answer: 0.0723 Energy can be: Correct Answer: transformed to different forms Velocity ratio is: Correct Answer: ideal mechanical advantage A 1 N weight has a kinetic energy of 1 J when its speed is: Correct Answer: 4.4 m/s The working stress of a material that has an ultimate strength of 490 MPa and a safety factor of 7 would be: Correct Answer: 70 MPa According to Hooke's Law, the stress in an elastic body is directly proportional to the strain if: Correct Answer: the elastic limit of the material is not exceeded The factor of safety is always expressed: Correct Answer: as a ratio When calculating the ultimate stress of a material, we should: Correct Answer: divide the maximum load by the original cross -sectional area Safe w orking stress is determined by: Correct Answer: dividing the ultimate strength by the factor of safety A 6 m long cantilever beam carries a concentrated load of 45 kN at its free end. What is the shear force at the wall? Correct Answer: 45 kN When classifying beams, the term simple beam refers to a beam: Correct Answer: that is supported at two ends The term _____ is used as a measure of the quantity of matter. Correct Answer: mass A 10 m long steel pipe when heated to increase its temperatur e by 85 °C, will expand approximately: Correct Answer: 1 cm The most common scale in use is the: Correct Answer: Celsius Four pieces of iron are heated in a furnace to high temperatures. The one at the highest temperature would appear: Correct Answer: wh ite The amount of heat required to completely melt 25 kg of ice from a temperature of -10 °C is approximately: Correct Answer: 8908 kJ "Heat will flow from a hot substance to a colder substance unaided, but it is impossible for heat to flow from a cold s ubstance to a hotter one without the aid of mechanical work" is: Correct Answer: A. the first law of thermodynamics B. Charles' Law C. the mechanical equivalent of heat D. Boyle's Law E. None of the above Answer: E The heat required to raise the temp erature of water at a pressure of 225 kPa from 0 °C to 124 °C is: Correct Answer: 520.72 kJ/kg When heat is supplied to a liquid in sufficient quantity to change the liquid to a vapour without changing the temperature, the heat supplied is known as: Corr ect Answer: latent heat of evaporation The dryness fraction of steam at a pressure of 400 kPa and a heat content of 2500 kJ/kg is: Correct Answer: 0.89