Average Velocity - General Physics - Past Paper, Exams of Physics

Download Average Velocity - General Physics - Past Paper and more Exams Physics in PDF only on Docsity! AJM:9/24/06 Page 1 of 1 Score /100 Physics 131 Midterm Fall 2005 Name PLEASE READ THIS FIRST: • Time limit: 55 minutes • Please remove hats and turn off and put away any communication devices. • You may use one sheet of prepared notes (8 ½ x 11, both sides). • Perform all of your work on these sheets. If you need more space, use the back of the same sheet. If you run out of space, ask me for a blank sheet of paper and staple it to the back of your exam before turning it in. • Read each problem carefully and be sure to pay attention to any hints that are provided. The credit you receive on each problem will depend more on how you get your answer than on what answer you get. There is no need to be as “wordy” as I ask you to be on homework, but you must show your work or give at least a brief explanation for every answer. I give no credit for unsupported answers. I do give partial credit for partially correct solutions, but only when I can determine that what you are doing is partially correct. • Make certain that all numerical answers are given with a reasonable number of significant digits (when in doubt, three is usually a good compromise) and that you have included appropriate and simplified units. • Check your answers for physical reasonableness whenever possible; I do deduct a small number of points for ridiculous answers that you don’t comment on. • You may use g = 10.0 m/s2 in all problems to make the arithmetic easier. 1. [20 pts total] A car uniformly accelerates for 4.0 s to a final speed of 29 m/s and covers a distance of 92 m during the process. What was a) its initial speed and b) its acceleration? [Hint: What was its average speed?] AJM:9/24/06 Page 2 of 2 2. [20 pts total] Suppose you leave your house and walk 4.0 miles west, then 5.0 miles in a direction 30 degrees east of north, and, finally, 2.0 miles south. You walk at a constant speed and the entire trip takes three hours. a) [8] What was your average velocity (a vector!) during the first hour of your walk? [This is easy, but don’t forget that you must support your answer.] b) [8] What was your average velocity (again, a vector!) for the entire walk? [Hint: Where do you end up after your three-hour walk?] c) [4] How long will it take you to get home if you walk straight there at the same constant speed?