Physics 23 Spring 212 Answer Sheet Print LAST Name: Rec Sec Letter EM Mini-Test First Name: Recitation Instructor & Final Exam Student ID: Gently remove this page from your exam when you begin. Write clearly in the space provided on this Answer Sheet the letter which you believe to be the best answer to each question on the End-Material Mini-Test and on the Final Exam, found on the following pages. ONLY THIS ANSWER SHEET will be looked at for scoring. Make sure your chosen answers are on it! Neither calculators nor notes can be used during the test. Relax, Read carefully, Think - and then read it again!!! If you become bogged down on a problem, go to the next one and return later to the hard one. Think before plunging into math manipulations. Basic principles may give you an easy answer. Never leave a multiple-choice question blank. Guess at the end if you must. EM Mini-Test Score = Final-Exam Score = Mini-Test Responses (1 pts each) Final-Exam Responses (1 pts each) Use a BLOCK letter to answer each question: A, B, C, or D (not lower case such a b or script such as D) em - 1) 1) 7) 13) em - 2) 2) 8) 14) em - 3) 3) 9) 15) em - 4) 4) 1) 16) em - 5) 5) 11) 17) 6) 12) 18)
Physics 23 Spring 212 END-MATERIAL MINI-TEST em-1. An object with a density less than the density of water is held below the surface of a lake so that the object is fully submerged. The magnitude of the buoyancy force acting on the object is its weight magnitude. A) less than B) equal to C) greater than D) the negative of em-2. A traveling wave on a string is described by the equation y(x,t) = 3 sin(2x + 24t) in SI units. The maximum speed of a particle on the string is times the wave to speed of the wave: A) 6 B) 2 C) 1 D) ¼ em-3. You are sitting in a race car. When you sound the horn in a racing car, you hear a frequency of 12 Hz directly from it. You now drive the car directly toward a cliff wall at a speed of one-fifth the speed of sound. What frequency do you hear for the horn s echo from the cliff wall? A) 8 Hz B) 1 Hz C) 15 Hz D) 18 Hz em-4. A rod has total length 4L, composed of two segments. Segment A has length L and segment B has length 3L. The thermal conductivity of the A substance is half that of B substance. The A-end of the rod is kept at temperature T o and the other end is kept at 6T o. What is the steady-state temperature at the junction J where the two segments join together? 9 A) 2T B) 3T C) 4 T D) 9 2 T B A 6 3L J L em-5. A monatomic ideal gas is taken through the cycle A B C A shown in the pressure-volume diagram at right. What is the value of the heat energy that flows into the gas in the process C A? A) 18 P V B) 9 P V C) 9 P V D) B A C 4 EM (Sp212)
Physics 23 Spring 212 FINAL EXAM Assume that g = 1 m/s 2 and that air-resistance is negligible unless otherwise stated! You can use front and back of any test sheets for diagrams and/or calculations. 1. The x-t graph at the right shows the motion of a particle. What is the sign of the numerical value of the x-component of acceleration at time A? A) negative B) zero C) positive D) decreasing x A t 2. A projectile is shot from a platform of height H above the ground with an initial velocity v o at angle θ above the horizontal. How much time elapses before the projectile is again at height H? A) 2v o sinθ /g B) 2H(v o ) 2 sinθ /g C) v o sinθ /g D) (H) ½ v o sinθ /g v o H θ a 3. An elevator is moving upward, but is slowing down with a constant acceleration magnitude of 3 m/s 2. You are standing on a weight scale in the elevator. If the weight scale reads 1 N, what is your acceleration? (Note g = 1 m/s 2 on this test) A) 13 m/s 2, down B) 1 m/s 2, down C) 3 m/s 2, up D) 3 m/s 2, down 4. Let M be the mass of the Earth. A ball of mass m is thrown straight up into the air. If the y-axis is directed upward, what is the value of the y-component of the gravitational force exerted on the Earth by the object? A) mg B) Mg C) mg D) Mg 5. A 2-kg block is attached to a 1-kg block by a light string. They are pulled along a rough surface with coefficient of friction µ =.5 by a horizontal force of magnitude 3 N applied to the 2-kg block, as shown in the figure. What is the tension T in the string? (Note g = 1 m/s 2 on this test) A) 1 N B) 15 N C) 2 N D) 3 N 3 N T=? 2 kg µ 1 kg FE - 1 (Sp212)
6. A small ball of mass M attached to a string of length R is moving in a vertical circle at constant speed, as shown in the figure at the right. Which of the following statements about the tension T in the string is true? A) T a < T c B) T a > T c C) T c < D) T b < T d b a v M R d c 7. A certain planet with radius R P has the same mass as Earth. On the surface of this planet, an object weighs 25 times as much as it weighs on the surface of Earth. The ratio R P /R Earth of the planet s radius to Earth s radius is A) 25 B) 1 / 25 C) 5 D) 1 / 5 8. A block of mass M is initially moving with speed V on a rough horizontal plane. The coefficient of kinetic friction is µ. The distance D traveled by the object as it comes to rest is A) V 2 /(2g) B) μv 2 /(2g) C) 2V 2 /(μg) D) V 2 /(2μg) 9. A one dimensional potential energy function is given by U(x) = 3x 3 7. The x-component of the force that produces this potential energy is: A) 9x 2 B) 9x 2 7 C) 9x 2 D) (3/4)x 4 + 7x 1. A satellite of mass m revolves in a circular orbit at a height h from the surface of Planet P. If R is the planet s radius and g p is the magnitude of the acceleration due to gravity at the surface of the planet, then the speed of the satellite is given by: A) [g p R 2 /(R+h)] 1/2 B) [g p R/(R+h)] 1/2 C) [g p R 2 /(R+h)] D) [g p gr/h] 1/2 FE - 2 (Sp212)
11. Two balls, one with twice the mass of the other, have the same kinetic energy. The linear momentum magnitude of the less massive ball is times the linear momentum magnitude of the more massive ball. A) 2 B) 2 / 2 C) 2 2 D) 1 12. Block A of mass m moving at speed V collides with Block B of mass 5m that is moving straight towards it with speed 2V. If Block A bounces straight backward with speed 3 V as a result of the collision, what is the 2 magnitude of the impulse delivered in the collision to Block B? A) mv/2 B) 5mV/2 C) 15mV 2 /4 D) 13mV 13. A disk can rotate about a fixed axis. If it starts from rest and is acted upon by a constant net torque, you can correctly infer that: A) the disk is in equilibrium. B) the elapsed time is proportional to the number of revolutions the disk has made. C) the angular speed of the disk is proportional to the number of revolutions that it has made. D) none of the above responses is true. 14. A solid cylinder of mass M and radius R rolls without slipping down an inclined plane that makes angle θ with the horizontal. At any instant while in motion, its rotational kinetic energy about its center of mass is what fraction of its total kinetic energy? A) ¼ sinθ B) ⅓ C) ( 2 / 5 ) R sinθ D) ½ 15. A bicycle is traveling North. The angular momentum vector of its front wheel is pointing. A) North B) East C) South D) West FE - 3 (Sp212)
16. A uniform solid circular disk of mass M and radius R is rotating horizontally about a central vertical frictionless axle with angular speed ω. Initially there is nothing on the disk. While the disk is rotating, two small boxes, each of mass m, are dropped vertically onto it at distances R/2 from the axle (see diagram). The boxes and disk are then observed to rotate with angular speed ω/2. Each box must have a mass m equal to m M m A) M/2 B) M C) 2M D) M/4 17. Near the surface of the earth, a pendulum oscillates with period T, and a block hanging from a spring oscillates vertically with the same period T. If these devices are taken into deep space where they experience zero gravitational force, what are their new oscillation periods? Pendulum Block & Spring A) Does not oscillate T B) T Does not oscillate C) Does not oscillate Does not oscillate D) T T 18. The spring of a simple harmonic oscillator is changed, but its mass and amplitude of oscillation are kept the same. If the new spring causes the frequency of its oscillation to double, the new maximum acceleration magnitude of the oscillator is times the original maximum acceleration magnitude. A) 2/π B) 2 C) 4 D) 2 The teaching staff of Physics 23 all wish you a happy and relaxing summer! FE - 4 (Sp212)