Important: This test consists of 30 multiple choice problems, each worth points.

Transcription

1 Physics 214 Practice Final B Fill in on the OPSCAN sheet: 1) Name 2) Student identification number 3) Exam number as 04 4) Sign the OPSCAN sheet Important: This test consists of 30 multiple choice problems, each worth points. Instructions: For each problem, choose the one answer that is correct or most nearly correct. Make a small mark, for your eyes only, near the letter of your choice. After you finish and check all the multiple-choice problems, transfer your answers to the computer sheet. Then, until you hand in the computer sheet, turn the sheet over and leave it face down. Only answers on the computer answer sheet will be graded. As your OPSCAN answer sheet will not be returned, record the answers on the test paper that you will keep. The correct answers will be displayed on the course web page, and you can find your score for this exam on CHIP. This is a closed book exam, but a crib sheet is provided. You may also use a calculator. Any form of cheating will result in severe penalties, which will include a score of zero for this exam and may result in a grade of F for the course and referral to the Dean of Students. All electronic devices must be securely put out of sight and may not be touched during the exam. All cell phones and pagers must be turned off. The only items you are allowed are the exam, the opscan sheet, a pencil and a calculator Page 1

2 FORMULAE AND CONSTANTS CONVERSION FACTORS 1 inch = 2.54 cm 1 ft = 30.5 cm 1 m = ft 1 km = miles 1 mile = 5280 ft 1 nautical mile = miles 1 kg = lbs (where g = 9.8 m/s 2 ) EQUATIONS s = d/t s = d/δt v = d/δt (vector) a = Δv/Δt (vector) v = v 0 + at d = v 0 t + ½at 2 d = ½(v + v 0 )t F = ma (vector) W = mg average speed instantaneous speed instantaneous velocity acceleration force weight Page 2

3 a = v 2 /R F = mv 2 /R F = GM 1 M 2 /R 2 W = Fd P = W/t KE = ½ mv 2 PE = mgh PE = ½ kx 2 P = mv FΔt = P f P i = Δp F external = 0, Δp = 0 centripetal acceleration centripetal force gravitational force work power kinetic energy potential energy potential energy momentum impulse momentum conservation Circumference = 2πR g = 9.8 m/s 2 G = N m 2 /kg 2 π = ω = θ/t = Δθ/Δt α = Δω/t ω = ω 0 t + αt θ = ω 0 t + ½ αt 2 Torque = Fl = τ L = Iω τ = Iα τ external = 0 L f L i = 0 circle accn of gravity gravitational constant angular velocity angular acceleration angular momentum torque & moment of inertia cons of ang momentum Page 3

4 P = F/A (pressure) P = ρgh (liquid) ρ = m/v kg/m 3 P A = 1.01 x 10 5 Pas Buoyant force = weight of liquid displaced ΔU = Q W PV = NkT ε = W/Q H ε = (T H T C )/T H (internal energy) (for a gas) (engine efficiency) (Carnot efficiency) T C = 5/9(T F -32) T F = (9/5)T C +32 (0 C = K) 1 calorie = joules Q = mcδt c = 1 cal/gm/ C for water 0.49 cal/gm/ C for ice Latent heat of vaporization for water = 540 cal/gm (heat required to turn water to steam at C) Latent heat of fusion for water = 80 cal/gm (heat required to melt ice at 0 o C) q e = -1.6 x C F = k q 1 q 2 /r 2 k = 9 x 10 9 N.m 2 /C 2 E = F/q (electric field) V = ΔPE/q (potential difference) ΔV = Ed (uniform E) I = q/t amps R = ΔV/I ohms R = R 1 + R 2 + R 3 (series) 1/R = 1/R 1 +1/R 2 +1/R 3 (parallel) P = εi = I 2 R watts (power) Page 4

5 MAGNETISM F/l = (2k'I 1 I 2 )/r Parallel Wires k' = 1 x 10-7 N/A 2 F = qvb perp Charged Particle Φ=BA Flux E = ΔΦ/t Induced EMF ΔV 2 = ΔV 1 (N 2 /N 1 ) Transformer WAVES v = fλ = λ/t v = F/μ wire v sound = 340m/s c = 3 x 10 8 m/s light nλ = dy/x Two slit y = λx/w Single slit mλ = dy/x Grating NUCLEAR 2He 4 alpha decay -1e 0 beta decay 1e 0 position decay Page 5

6 1. The electric potential increases between two points from 82V to 586V. What is the magnitude of the change in potential energy when a charge of -2x10-4 C is moved from the low voltage point to the high voltage point? A) 5.5 x 10-2 B) 9.1 x 10-2 C) 11.7 x 10-2 D) 10.1 x 10-2 E) 1.6 x A current of 2.8 amps flows through a battery for 9 minutes. How much charge in coulombs passes through the battery in that time? A) 632 B) 856 C) 193 D) 2212 E) An ice cube of mass 100 g and at 0 o C is dropped into a Styrofoam cup containing 400 g of water at 25 o C. The heat of fusion of ice is 80 cal/g and the specific heat capacity of water is 1.0 cal/g C. Assuming the cup doesn't exchange any heat, the final temperature of the system will be which of the following? A) +5.0 o C. B) 0 o C. C) 4 o C. D) +2.5 o C. E) -10 o C. 4. Three blocks are being pulled across a frictionless horizontal floor as shown in the diagram. What is the tension between the first and second bock in Newtons? A) 240 B) 500 C) 300 D) 150 E) 160 Page 6

7 5. A football is thrown upward at an angle of 30 0 above the horizontal. At the highest point, and ignoring friction, how many of the following statements are true? The vertical acceleration is zero The total energy of the football has not changed There is an horizontal acceleration The momentum of the football has not changed The horizontal velocity has not changed A) 3 B) 4 C) 5 D) 1 E) 2 6. A transformer has 200 turns on the primary and 20 turns on the secondary. The primary is connected to a alternating current source of 100 millivolts. What is the voltage induced in the secondary? A) 1000 millivolts. B) zero. C) 20 millivolts. D) 10 millivolts. E) 4000 millivolts. 7. You have exactly 4 resistors: one 3, one 4, one 5, and one 6. How can you combine these to make a 2 resistor? (The symbol stands for "ohm".) A) Connect the 3 resistor in parallel with the 4 resistor. B) Connect the 3 resistor in series with the 5 resistor. C) Connect all four resistors in parallel with each other. D) You can't make a 2 resistor from the ones listed. E) Connect the 3 resistor in parallel with the 6 resistor. 8. A coil of wire has 60 turns and crossectional area = 0.02m 2 forms a closed circuit with resistance of 10ohms and has it's plane perpendicular to a magnetic field B = 1.5T. The coil is rotated by 90 0 so that it's plane is parallel to the field in 0.2seconds. What is the average current induced in the coil in amps? A) B) 0.21 C) 0.90 D) 0.18 E) 0.71 Page 7

8 9. Three equal negative charges are placed at three of the four corners of a square. What is the direction of the electric field at the remaining corner of the square? A) along a side of the square away from one of the charges. B) no direction, zero field. C) along the diagonal connecting this corner and another charge, toward the other charge. D) along a side of the square toward one of the charges. E) along the diagonal connecting this corner and another charge, away from the other charge. 10. Three bulbs each 10 watts are connected in parallel as shown. One of the lights fails. Which of the following statements is correct? A) The two remaining bulbs decrease in brightness B) The two remaining bulbs stay at the same brightness C) The current drawn from the battery increases D) The two remaining bulbs increase in brightness 11. Two suction cups each of area A = 100 centimeter squared are pressed together so that all the air is removed. Two students try and pull them apart. What is the value of F, in Newtons, needed to separate the cups? A) 1.01 x 10 B) 1.01 x 10 3 C) 1.01 x 10 9 D) 1.01 x 10 5 E) 1.01 x 10 7 Page 8

9 12. A boat floating in a large pool is loaded with wood blocks. The water level at the pool's edge is marked with a red line. The blocks are now thrown overboard and float outside the boat. When the water becomes calm again which of the following statements is true? A) the red line is slightly lower than the water level. B) the red line is still at the water level. C) the red line is slightly higher than the water level. 13. A pure sample of a radioactive substance has 16x10 12 atoms and the half life is 3 minutes. how long does it take until 5x10 11 atoms of the substance have not yet decayed? A) 24 minutes B) 96 minutes C) 18 minutes D) 32 minutes E) 15 minutes 14. A piano tuner finds that the frequency of a note is 417Hz instead of 396Hz. By what percentage should the tension in the string be changed to correct this? A) 5% B) 3% C) 7% D) 10% E) 2% 15. The orbit of Earth about the Sun is not a circle; Earth is closer to the Sun in December than it is in June. Thus, the speed of Earth as it moves about the Sun is A) greater in June than it is in December. B) steadily decreasing all year long. C) the same all year long. D) steadily increasing all year long. E) greater in December than in June. 16. The atomic number of an atom is the number of A) protons in the nucleus. B) neutrons in the nucleus. C) sum of protons and neutrons in the atom. D) sum of protons and electrons in the atom. E) electrons in the nucleus. Page 9

10 17. A hydraulic jack is used to lift a load of weight 1000 N. The load-bearing cylinder has a radius of 4 cm, and the other piston has a radius of 1 cm. What force must be exerted on the smaller piston to support the load? A) 4000 N B) 1000 N C) 125 N D) 62.5 N E) 250 N 18. An organ pipe of length 3.0 m has one end closed. The two longest possible wavelengths for standing waves inside the pipe are A) 12 m and 6 m. B) 12 m and 4 m. C) 9 m and 6 m. D) 3 m and 1.5 m. E) 6 m and 3 m. 19. A figure skater is spinning with her arms extended. She now pulls her arms close to her body. Which of the following is correct? A) Her angular momentum decreases. B) Her moment of inertia decreases. C) Her angular momentum increases. D) Her kinetic energy decreases E) Her moment of inertia increases. 20. A person weighing 500Newtons rides on a Ferris wheel sitting on a bathroom scale.at the highest point the scale reads zero while the person continues to move in a circular path. What is the centripetal force in Newtons? A) B) 700 C) 51 D) 0 E) 500 Page 10

11 21. Light with a wavelength of 500nanometers strikes a double slit with a spacing of 0.4mm. An interference pattern is observed on a screen 2 meters away. How far from the center of the screen in millimeters is the first bright line? A) 30 B) 2.5 C) 1.5 D) 25 E) Two people sit face to face on chairs which are free to roll without friction. They push each other with a force of 50 N and move apart. Person A, whose mass (including the chair) is 80 kg, moves to the left at 2.5 m/s. Person B, whose mass (including the chair) is 50 kg, A) moves to the right at 10 m/s. B) moves to the right at 2.5 m/s. C) moves to the right at 4 m/s. D) moves to the right at 6m/s E) moves to the right at 3.16 m/s. 23. A car starts from rest and travels 400m in 5.4 seconds with constant acceleration What is the speed of the car in m/s after 5.4 seconds? A) 156 B) 148 C) 35 D) 96 E) A particle with a charge of 1.6x10-19 C is moving with a velocity of 300m/s at 90 0 to a uniform magnetic field of strength 0.5T. What is the magnitude of the force acting on the particle in Newtons? A) 2.4 x B) 9.6 x C) 9.6 x D) 0 E) 2.4 x Page 11

12 25. A household circuit rated at 120 Volts is protected by a fuse rated at 15 amps. What is the maximum number of 100 watt light bulbs which can be lit simultaneously in parallel in this circuit without blowing the fuse? A) 20 B) 4 C) 8 D) 24 E) In a nuclear reactor, chain reaction refers primarily to A) the bonding of radioactive nuclei. B) The radioactive decay of uranium C) the separation of uranium-235 from uranium-238. D) the production of plutonium from uranium. E) the role of neutrons in the initiation and continuation of nuclear fission. 27. A string is held taut between two supports 2.0 m apart. The two longest possible wavelengths for standing waves are: A) 4 m and 3 m. B) 3 m and 1.5 m. C) 2 m and 1 m. D) 3 m and 2 m. E) 4 m and 2 m. 28. How much work in joules can a motor rated at 500 watts output in 10 seconds? A) 1000 B) 5000 C) 50 D) 2000 E) What is the process of nuclear fission as in a nuclear power plant? A) high energy particles are released from a nucleus that is at rest. B) two heavy nuclei are induced to decay simultaneously. C) a nucleus is split into two less massive nuclei. D) a nucleus is bombarded with another nucleus in order to induce an alpha decay. Page 12

13 30. A bullet of mass 150 grams is fired into a block of mass 4kg with a velocity of 200m/s. The bullet penetrates the wood and stops. What is the speed of the system in m/s just after the bullet stops? A) 10.4 B) 9.3 C) 7.2 D) 5.2 E) 7.5 Page 13

14 Answer Key 1. D 2. E 3. C 4. C 5. E 6. D 7. E 8. C 9. C 10. B 11. B 12. B 13. E 14. D 15. E 16. A 17. D 18. B 19. B 20. E 21. B 22. C 23. B 24. A 25. E 26. E 27. E 28. B 29. C 30. C Page 14