EDEXCEL NATIONALS UNIT 6 MECHANICAL PRINCIPLES and APPLICATIONS ASSIGNMENT No. 4 NAME: I agree to the assessment as contained in this assignment. I confirm that the work submitted is my own work. Signature Date submitted Learning outcomes On completion of this unit a learner should: 1 Be able to determine the effects of loading in static engineering systems 2 Be able to determine work, power and energy transfer in dynamic engineering systems 3 Be able to determine the parameters of fluid systems 4 Be able to determine the effects of energy transfer in thermodynamic systems. FEEDBACK COMMENTS This assignment only assesses P7, P8, P9, M3 and M4. Grade Awarded: Assessor Signature Date: Internal verifier Signature Date:
Grading grid In order to pass this unit, the evidence that the learner presents for assessment needs to demonstrate that they can meet all of the learning outcomes for the unit. The criteria for a pass grade describe the level of achievement required to pass this unit. Grading criteria To achieve a pass grade the evidence must show that the learner is able to: P1 calculate the magnitude, direction and position of the line of action of the resultant and equilibrant of a non-concurrent coplanar force system containing a minimum of four forces acting in different directions. P2 calculate the support reactions of a simply supported beam carrying at least two concentrated loads and a uniformly distributed load To achieve a merit grade the evidence must show that, in addition to the pass criteria, the learner is able to: M1 calculate the factor of safety in operation for a component subjected to combined direct and shear loading against given failure criteria. M2 determine the retarding force on a freely falling body when it impacts upon a stationary object and is brought to rest without rebound, in a given distance. To achieve a distinction grade the evidence must show that, in addition to the pass and merit criteria, the learner is able to: D1 compare and contrast the use of D Alembert s principle with the principle of conservation of energy to solve an engineering problem. D2 evaluate the methods that might be used to determine the density of a solid material and the density of a liquid. P3 calculate the induced direct stress, strain and dimensional change in a component subjected to direct uniaxial loading and the shear stress and strain in a component subjected to shear loading. M3 determine the thermal efficiency of a heat transfer process from given values of flow rate, temperature change and input power. P4 solve three or more problems that require the application of kinetic and dynamic principles to determine unknown system parameters. M4 determine the force induced in a rigidly held component that undergoes a change in temperature. P5 calculate the resultant thrust and overturning moment on a vertical rectangular retaining surface with one edge in the free surface of a liquid. P6 determine the up-thrust on an immersed body. P7 use the continuity of volume and mass flow for an incompressible fluid to determine the design characteristics of a gradually tapering pipe. P8 calculate dimensional change when a solid material undergoes a change in temperature and the heat transfer that accompanies a change of temperature and phase. P9 solve two or more problems that require application of thermodynamic process equations for a perfect gas to determine unknown parameters of the problems.
ASSIGNMENT DETAILS The diagram shows two tanks of liquid. Tank 1 is heated by hot gas passing through a heating coil as shown. When the liquid is at the right temperature, a tap is opened and the hot liquid passes along to tank 2 through an insulated pipe. PART 1 At a given moment in time, the flow rate is 5 kg/s. Calculate the following. 1. The velocity of liquid flowing in the pipe. 2. The velocity of the surface of tank 1 as it falls. 3. The velocity of the surface of tank 2 as it rises. Tank 1 has a cross sectional area of 6 m 2. Tank 2 has a cross sectional area of 4 m 2. The pipe has a bore of 80 mm. The liquid has a density of 920 kg/m 3. PART 2 The liquid in tank 1 is heated up and released into the pipe. Calculate the following. 1. The change in length of the pipe if it is free to expand. 2. The stress and strain in the pipe if it is not free to expand. The pipe length is 5 m. The modulus of elasticity for the pipe is 200 GPa The coefficient of linear expansion for the pipe is 15 x 10-6 K -1 The temperature of pipe before the liquid is released is 20 o C The temperature of pipe after the liquid is released is 160 o C
PART 3 The liquid in tank 1 is heated from 20 o C to 160 o C in 40 minutes. Calculate the following. 1. The heat transfer 2. The average rate of heat transfer. The specific heat capacity of the liquid is 1970 J/kg K. The mass heated up in the tank is 400 kg. PART 4 The heating coil uses hot gas that becomes cooled as it passes through the coil. Calculate the following. 1. The volume of hot gas flowing at inlet. 2. The velocity of the gas at entrance. 3. The volume of the cool gas at exit. 4. The velocity of the cool gas at exit. The inlet temperature of the gas is 500 o C. The absolute inlet pressure is 5 bar (500 kpa). The exit temperature of the gas is 110 o C. The absolute pressure at exit is 1.2 bat (120 kpa) The mass flow rate of the gas is 0.15 kg/s. The characteristic gas constant is 190 J/kg K The bore of the coil is 50 mm.
STUDENT and TUTOR GUIDE TO DOING THIS ASSIGNMENT If you are unable to get started or make progress you should seek assistance from your tutor and your grades will be determined by how much assistance you need. Tutors may purchase the full solution from admin@www.freestudy.co.uk. This also includes a Mathcad file for solving variations of the problem by changing the data. This will enable tutors to set different assignments and so reduce the risk of copying. TO OBTAIN A DISTINCTION You should do all parts correctly with the minimum of assistance. Your solutions should be exceptionally clear and accurate and the symbols used should be clearly indicated in the formula you create to evaluate your answers. Your answers should be checked for accuracy by for example, calculating the original data from your answers to see that it is the same. You should show clearly all the principles involved in the solution and state who they are attributed to. You should make correct use of units and multiples. TO OBTAIN A MERIT You should do all parts with only minor errors. You should not require more than basic assistance to complete the assignment. You should draw clear diagrams illustrating the principles used to arrive at your solutions. You should make correct use of units and multiples. TO OBTAIN A PASS You should attempt all parts and demonstrate that you understand the principles involved to solve the answers. You will probably have asked for help in drawing a free body diagram and in resolving the forces appropriately. You should demonstrate that your calculations are accurate and use the correct units and multiples.