ENPH 131 - Midterm Solutions 2014 .pdf - Faculty of Engineering and Department of Physics Engineering Physics 131 Midterm Examination Monday 7:00 pm

# ENPH 131 - Midterm Solutions 2014 .pdf - Faculty of...

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1 Faculty of Engineering and Department of Physics Engineering Physics 131 Midterm Examination Monday February 24, 2014; 7:00 pm – 8:30 pm 1. No notes or textbooks allowed. 2. Formula sheets are included (may be removed). 3. The exam has 9 problems and is out of 50 points . Attempt all parts of all problems. 4. Show all work in a neat and logical manner. Questions 1 to 4, 8(a) and 9 do not require detailed calculations and only the final answers to these questions will be marked. For the rest of the questions, details and procedures to solve these problems will be marked. 5. Write your solution directly on the pages with the questions. Indicate clearly if you use the backs of pages for material to be marked. 6. Non-programmable calculator allowed. Turn off all cell-phones, laptops, etc. and put them in your backpack. DO NOT separate the pages of the exam containing the problems. LAST NAME: ______________________________________ FIRST NAME: ______________________________________ ID#: ___________________ Please circle the name of your instructor: B01: Kaminsky B02: Beach B03: McDonald B04: Tang B05: Wheelock B06: Ropchan
2 Please do not write in the table below. Question Value (Points) Mark 1 5 2 2 3 5 4 2 5 7 6 7 7 8 8 8 9 6 Total 50
3 1.[5 Points]Cars A and B begin at distances sA= 1.0 km and sB= 1.5 km from an intersection, as measured bumper to stopping line. The vehicles are initially travelling at 18 km/h and 36 km/h, respectively, and they are accelerating at constant rates aA= 0.05 m/s2and aB= 0.10 m/s2. Neither vehicle, however, will exceed the posted speed limit of 54 km/h. Each lane is 4.0 m wide. Expressed in a coordinate system centered on the intersection, and whose axes are aligned with the two roads, the vehicle positions are rA= (±sA±4.0, ±2.0) m and rB= (±2.0, sB+4.0) m. The distance between the vehicles is |rA/B| = |rA±rB|. Of the 11 lines shown on the three graphs below, 5 correctly describe the evolution in time of sA, sB, vA(speed of A), vB(speed of B) and |rA/B|. Match those 5 lines to the corresponding quantity by writing the appropriate numbers in the blanks provided. sAis described by curve sBis described by curve vAis described by curve vBis described by curve |rA/B| is described by curve 3 4 7 5 9
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