EF 152 Final Exam Fall 2018 Page 1 Copy 160

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1 EF 152 Final Exam Fall 2018 Page 1 Copy 160 Name: Seat Assignment: Specify your EXAM ID on the right. Use 000 if you don t know your exam ID. Circle your TEAM SECTION 11:10 12:40 2: A216 Matthew B216 Matthew C216 Matthew A217 Cole B217 Cole C217 Cole A218 Landon Instructions Do not open the exam until instructed to do so. This exam consists of three 1 pt problems, two 4 pt problems, and two 7 pt problems for each of the 4 modules. Do not leave if there is less than 5 minutes to go in the exam. When time is called, immediately stop writing, remain seated, and pass your exam to the center aisle. Working after time is called results in an automatic deduction. Turn your equation sheets in with your exam. Guidelines Assume 3 significant figures for all given numbers unless otherwise stated Show all of your work no work, no credit Write your final answer in the box provided Include units for all answers

2 EF 152 Final Exam Fall 2018 Page 2 Copy (1 pt) A 200 N box is at rest on a ramp. Jeremy Pruitt pushes the box with a force P parallel to the top of the box. Using the given coordinate system, which of the following is the correct equilibrium equation for forces on the box in the x direction if you want to determine the minimum force P required to start sliding the box up the incline? P sin 30 = 0 P 200 sin 30 - sn = 0 P 200 sin 30 - N = 0 P 200 cos 30 - s N = 0 2. (1 pt) A shark tank has an underwater circular viewing window as shown. What is the average gauge pressure on the window? (3*1000*9.81) Pa (3*π*2 2 *1000*9.81) Pa (40*30*3*1000*9.81) / ( π*2 2 )Pa 3. (1 pt) In a Venturi tube, how do the pressures at A and B compare? PA < PB PA = PB PA > PB A B

3 EF 152 Final Exam Fall 2018 Page 3 Copy (4 pt) A professor is hung from 100 ft long, 1/16 diameter steel cable. The cable stretches 4.0 inches. How much does the professor weigh? (Esteel = 30x10 6 psi) 5. (4 pt) A 0.92 kg bocce ball has a volume of m 3. The ball is completely submerged in water. What is the magnitude and direction (up or down) of its acceleration the instant it is released?

4 EF 152 Final Exam Fall 2018 Page 4 Copy (7 pt) The supply system for a fountain is shown here. What gauge pressure is required at A in order to have water exiting the fountain at 60 ft/s? 7. (7 pt) A bracket of negligible weight has a factor of safety of 4.0 for pin A when supporting the two loads as shown. At what load would the pin fail (break)? (Point B is a roller connection, FBD required) lb B 0.7 ft A 1.8 ft 0.75 ft 150 lb

5 EF 152 Final Exam Fall 2018 Page 5 Copy (1 pt) What are the signs of the components of the net force on charge 3 due to the other two charges? (All charges have the same magnitude and are the same distance apart) Charge 1 -Q a +x, +y -x, +y -x, -y +x, -y 0,0 a a Charge 2 +Q y -Q Charge 3 x 9. (1 pt) A negatively charged particle is located at the origin and has a velocity of 8î m/s. What is the direction of the magnetic field at (0î +4ĵ +0k ) m? i -i j -j k -k 10. (1 pt) A negatively charged particle is located at the origin. What is the direction of the electric field at (0î +4ĵ +0k ) m? i -i j -j k -k

6 EF 152 Final Exam Fall 2018 Page 6 Copy (4 pt) Find the electric field (i, j notation) at the origin. -10 C 12 C 0.20m 0.40m y x 12. (4 pt) The voltage difference between points A and B is 9 Volts. What is the voltage drop across the 6 resistor? A 6Ω 4Ω 2Ω B

7 EF 152 Final Exam Fall 2018 Page 7 Copy (7 pt) Determine the power dissipated in the 4 ohm resistor in the circuit shown. 14. (7 pt) A particle with a charge of -2 C and a velocity of 4x10 7 î m/s moves through a magnetic field of (2î +18ĵ +16k ) µt and an electric field of 3000 ĵ N/C. Determine the net force on the electron (î ĵ k notation).

8 EF 152 Final Exam Fall 2018 Page 8 Copy (1 pt) What is the change in internal energy in process ACB? p 500 kpa B C 100 kpa Constant Temperature A V 0.05 m m kpa (0.20 m 3 ) -500 kpa (0.20 m 3 ) 600 kpa (0.20 m 3 ) 600 kpa (0.05 m 3 ) ln (.25/.05) 16. (1 pt) A fixed amount of an ideal gas has 100 J of heat added to it and 70 J of work done on it. What is its change in internal energy? 0 J -30 J +30 J -170 J +170 J 17. (1 pt) In a particular freezer cycle, in one second there are 650 Joules of heat exhausted to the room, 400 Joules of heat extracted, and the freezer consumes 250 Watts of electricity. What is the coefficient of performance? 250/ / / / / /250

9 EF 152 Final Exam Fall 2018 Page 9 Copy (4 pt) A room is cooled by a small air conditioning unit with a 500W motor. Its coefficient of performance is 2.6. How long will it take to remove 420 kj of heat from the room? 19. (4 pt) A power plant takes in steam at 888 K to power turbines and then exhausts the steam at 250 K. The heat input rate is 150 MW. If the actual efficiency is 1/3 of the ideal efficiency, what is the power output of the plant?

10 EF 152 Final Exam Fall 2018 Page 10 Copy (7 pt) 0.5L of an ideal diatomic gas at 15 C and 2.5 atm absolute pressure produces 179 J of work when it undergoes adiabatic expansion to a final volume of 4.0L. What is the final temperature of the gas? (Use =1.4) 21. (7 pt) 150 g of ice at -10 C is added to 500 g of water at 65 C J of heat is lost to the surroundings. What is the equilibrium temperature?

11 EF 152 Final Exam Fall 2018 Page 11 Copy (1 pt) A light ray passes from air (n=1.0) into diamond (n=2.42) at an incident angle of i=30. Which is true for the refracted light? it will be bent closer to the surface (interface of air and diamond) It will be bent closer to the normal angle of refraction = angle of incidence there will be no light refracted since i > crit 23. (1 pt) With one drummer drumming, the sound level at a certain location is measured as 60 d. With twelve drummers drumming with the same intensity, what will the sound level be at the same location (in d? log log log log log (1 pt) One of the 11 pipers piping has a closed-open pipe and an open-open pipe of the same length. For the fundamental frequency, which is true? open > closed fopen > fclosed vopen > vclosed nopen > nclosed None are correct

12 Y (m) EF 152 Final Exam Fall 2018 Page 12 Copy (4 pt) A 0.2 kg star is attached to the end of a spring (k = 44 N/m). It oscillates in simple harmonic motion with a maximum speed of 25 m/s. What is the amplitude of the motion? 26. (4 pt) The traveling wave shown has a frequency of 0.15 Hz. Use the wave equation to determine the y-position of the particle at x=5.0m for t=8.9 sec. (For t=0 and x=0, y=0) X (m)

13 EF 152 Final Exam Fall 2018 Page 13 Copy (7 pt) A partridge pecks at a 160 gram pear and it oscillates about point P. What is the period of oscillation if the pear has a mass moment of inertia of I cm=0.005 kg m 2? 85 cm 30 cm 20 cm P CM 28. (7 pt) A 4997 khz ultrasonic wave is emitted into a vein where the speed of sound in blood is 1500 m/s. The wave reflects off blood cells moving toward the stationary receiver. If the speed of red blood cells is m/s, what is the beat frequency detected by the receiver?