Physics E-1ax HW 1 1 Physics E-1ax Offline Homework 1 Vectors, Position, and Velocity 10 points total Assignment due date : 6:00pm on Tuesday, Sept. 6th ( we can’t accept late homework ) Homework format : Please write your answers to these questions on a separate sheet of paper with your name and your section TF’s name written at the top. You are encouraged to work with your classmates on these assignments, but please write the names of all your study group members on your homework. How to submit homework : Upload a single PDF document scanned copy of your assignment to the Canvas website under “Offline Homework 1” for Week 1. For questions, please e-mail the administrative account ( [email protected] ) Grading policy : Each part (a, b, c) of each question is worth 1 point. You will earn that point if you make a good-faith effort to solve that part of the problem completely . We will not be grading for whether your answer is correct or incorrect, but of course for your own learning you should try to get the right answer! You will get a zero for any part of a question that is incomplete or neglected. For help: Consult the Physical and/or virtual help room hours (schedule to be posted on Canvas) and/or ask questions on Piazza . 1. Vectors and Components: The Electrocardiogram (4 pts). Before doing this problem it may help you to look at the “EKG Background & Example” section near the end of this document . a) Determine the mean electrical axis for each EKG below. Be sure to show a clear diagram of the components and the overall axis, and show all calculations explicitly. Do any of the axes lie outside of the normal range? Patient A:
Physics E-1ax HW 1 2 Patient B: Patient C:
Physics E-1ax HW 1 3 b) The mean electrical axis of the heart does not always lie along the center of the heart; usually, it lies somewhat to the left of the center of the heart. (That is, although the center of the heart lies at an angle of ~50°, the mean electrical axis usually is closer to ~30°.) Given that the left ventricle is larger and stronger than the right ventricle, explain why the electrical axis of the heart normally lies to the left. (Hint: the mean electrical axis is the sum of many “depolarization vectors.”) A clear diagram will be essential to your answer! c) A 23-year-old female patient had the EKG shown at right. She was diagnosed with right ventricular hypertrophy , a condition in which her right ventricle was abnormally enlarged. In what way does the EKG support this diagnosis? Provide a quantitative calculation and a qualitative explanation. d) You may have noticed that there are no axes on these EKG’s. The scale of these graphs is set by the rectangular calibration pulse at the far left of each EKG trace. This pulse has a height of 1 mV and a width of 0.20 seconds. Given this information, what is the heart rate (in beats per minute) of the female patient whose EKG is shown at right?