Belt Material - Mechanics of Machines and Materials - Exam, Exams of Materials science

Download Belt Material - Mechanics of Machines and Materials - Exam and more Exams Materials science in PDF only on Docsity! Page 1 of 3 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 2 Examinations 2011/12 Module Title: Mechanics of Machines Module Code: MECH7013 School: Mechanical and Process Engineering Programme Title(s): Bachelor of Engineering (Honours) in Mechanical Engineering Programmes Code(s): EMECH_8_Y2 External Examiner(s): Mr John J. Hayes, Prof. Sean Leen Internal Examiner(s): Dr Andrew Cashman Instructions: Answer THREE questions. Duration: Two Hours Sitting: Autumn 2012 Requirements for this examination: Graph paper and mathematical tables to be provided 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 3 Q1. (a) Show that for a flat belt experiencing the centrifugal effect:  T1 mv 2 T2 mv 2  e  where m = mass per unit length of the belt material and v = belt velocity. (12 marks) (b) A belt transmits 20 horsepower from a pulley 0.9m diameter, which runs at 300rpm. The angle of embrace of the belt and pulley is 160° and the coefficient of friction between belt and pulley is 0.25. The belt is 6.4mm thick and has a density of 1107.3kg/m 3 . Determine the minimum belt width for a maximum belt stress of 2MPa. (1 horsepower = 746W) (13 marks) Q2. (a) Assuming that the connecting rod is large in comparison with the crank radius of a reciprocating engine, obtain expressions for the displacement and acceleration of the piston in terms of the angular velocity of the crank, connecting rod length, crank length and crank angle past inner dead centre. (10 marks) (b) A reciprocating engine has the following particulars: Stroke 228.6mm, connecting rod length 457.2mm and speed 250rpm. Sketch on a piston displacement base the curve of piston acceleration. (15 marks)