UNIVERSITY OF BRITISH COLUMBIA 2017/2018 WINTER SESSION SESSIONAL EXAMINATION PHYSICS 170 MECHANICS I 8:30 am to 11:00 am, Friday, April 20, 2018 MARKS This exam counts for a total of 60 marks towards your Final Grade for the course. The exam consists of 4 questions. The questions are worth the same number of marks. Write all work to be marked in the Answer Booklet provided. NUMERICAL ANSWERS Write numerical answers to three significant figures with units. CALCULATOR You may use a graphing calculator. INFORMATION SHEET You may consult one 8 1/2 inch by 11 inch hand-written double-sided Information Sheet. Your Information Sheet must not contain any sample problems or solutions to sample problems. Put your name and student number on your Information Sheet. You must hand in your Information Sheet with your Answer Booklet in order for your exam to be marked.
PHYSICS 170 MECHANICS I Final Exam: 8:30 am to 11:00 am, Friday April 20 2018 QUESTION 1 The diagram below shows a rigid body AB in the horizontal plane acted on by a force F = (-400?+ 300] + 200k) N at B and by a couple moment M = (5007 + 100] + 400k) N · m where I, j, k are the usual Cartesian unit vectors. A cylinder with weight 900 N hangs from D. AB is held in equilibrium by a cable BC and by a square rod at A which fits loosely through the square hole at the end AB. The weight of AB may be neglected. a) Draw a large, clear free-body diagram for AB. b) Determine Cartesian component force equations of equilibrium for AB. c) Determine a vector moment equation of equilibrium in determinant form for AB. d) Determine Cartesian component moment equations of equilibrium for AB. e) Determine numerical values for the Cartesian components of reaction at A and the tension in the cable. Z Im A F 2 n D B Im -
PHYSICS 170 MECHANICS I Final Exam: 8:30 am to 11:00 am, Friday April 20 2018 QUESTION 2 In the diagram below, particle C travels along the curved guide due to the rotation of the arm AB. Motion is in the horizontal plane. The guide is described by the equation r = 0.60 m where 0 is in radians measured from the horizontal. The mass of C is 3.0 kg. The size of C may be neglected. The arm exerts a force F on C perpendicular to AB. The slot exerts a normal force Ñ on C. In addition, a force S acts on C in the direction opposite to the velocity of C. At the instant shown: 0 = 120 0 è = 0.2 rad/s 2 ? = 0.3 rad/s r = 1.257 m + = 0.12 m/s The magnitude of Šis 0.4 N. F = 0.18 m/s 2 dr / d0 = 0.6 m/rad a) Draw a large, clear free-body diagram for C at the instant shown. b) Determine the numerical value of the speed