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Unformatted text preview: lenoir (wml297) oldhomework 06 Turner (58220) 1 This print-out should have 12 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A quarterback takes the ball from the line of scrimmage, runs backward for 16 yards, then runs sideways parallel to the line of scrim- mage for 15 yards. At this point, he throws a 27 yards forward pass straight downfield perpendicular to the line of scrimmage. What is the magnitude of the footballs resultant displacement? Correct answer: 18 . 6011 yards. Explanation: Let the x direction be parallel to line of scrimmage. Given : y 1 =- 16 yards , x = 15 yards , and y 2 = 27 yards . y tot = y 1 + y 2 =- 16 yards + 27 yards = 11 yards x tot = x = 15 yards The displacements are perpendicular, so d = radicalBig ( x tot ) 2 + ( y tot ) 2 = radicalBig ( 15 yards) 2 + (11 yards) 2 = 18 . 6011 yards . 002 (part 1 of 5) 10.0 points A commuter airplane starts from an airport located at the origin. First it flies to city A located 120 km away from the airport in a direction 40 North of East. Next it flies 56 . 9 km at 40 West of North to city B. Finally it flies 181 km due West to city C. A B C O a c b r N N E W What is the x-component of the vector vector b ? Consider E to be the positive x axis and N to be the positive y axis. 1. b x =- b cos 2. b x =- b sin correct 3. b x = b tan 4. b x =- b tan 5. b x = b cos 6. b x = b sin Explanation: Let : b = 56 . 9 km and = 40 . For vectorv = ( v x , v y ) and vectoru = ( u x , u y ) , vectorr = vectoru + vectorv = ( v x + u x , v y + u y ) b | b x | | b y | Also, for < 90 (as in this problem), vector b is in the second quadrant; i.e. , its x component is negative and its y component positive: b x =- b sin =- (56 . 9 km) sin40 =- 36 . 5746 km ....
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This note was uploaded on 04/15/2010 for the course PHY 12343 taught by Professor Turner during the Spring '10 term at University of Texas at Austin.
- Spring '10