Thermofluids Exam Document (MECH6010) at Cork Institute of Technology, 2012, Exams of Materials science

Download Thermofluids Exam Document (MECH6010) at Cork Institute of Technology, 2012 and more Exams Materials science in PDF only on Docsity! Page 1 of 5 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 2 Examinations 2012 Module Title: Introductory Thermofluids Module Code: MECH6010 School: Mechanical & Process Engineering Programme Title: Bachelor of Engineering (Honours) in Mechanical Engineering Bachelor of Engineering (Honours) in Biomedical Engineering Programme Code: EMECH_8_Y1 EBIOM_8_Y1 EOMNI_8_Y1 External Examiner(s): Mr J.J. Hayes, Prof. S. Leen, Mr G. Clerkin, Dr L. McNamara Internal Examiner(s): Mr Sean Williams Instructions: Answer any THREE questions. All Questions carry equal marks. Duration: 2 Hours Sitting: Summer 2012 Requirements for this examination: Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination. If in doubt please contact an Invigilator. Page 2 of 5 Q1. (a) Show that the magnitude of the resultant force acting on a plane surface of a completely submerged plate in a fluid is: FR = PC A FR = Resultant Force, PC = Pressure at the centroid of the surface, A = Area of the surface (10 marks) (b) Determine the magnitude and direction of the resultant force (FR) on the cylindrical dam section (submerged curved surface) shown in Figure 1 (on page 5). The dam is 30 metres wide and water has a density of 1000 kg/m 3 . (10 marks) Q2. (a) Show that the difference in pressure between two forces acting on the top and bottom surfaces of a submerged plate is the buoyant force. (6 mark) State Archimedes Principle and explain how it is verified in part (a). (2 marks) (b) Establish the necessary and sufficient condition for the stability of a hot-air balloon shown in Figure 2. (4 marks) (c) The hot-air balloon shown in Figure 2 (on page 5) has an inflated volume of 270 m 3 and is filled with helium at atmospheric pressure and temperature. In an uninflated condition the balloon plus gondola, balloon equipment and two people has a total mass of 200 kg. The densities of air and helium at atmospheric conditions are 1.2062 kg/m 3 and 0.1664 kg/m 3 , respectively. Neglect the volume values of the gondola, balloon equipment, etc. Note: The balloon is stationary at this altitude. i. Calculate the tension T in the vertical cable attached to the balloon before it is released. (6 marks) ii. Is it possible for a man weighing 75kg to hold the balloon in place while standing on the ground. (2 marks)