final3 - UCSD Physics 2A Winter 2009 Instructor : Prof....

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Unformatted text preview: UCSD Physics 2A Winter 2009 Instructor : Prof. Vivek Sharma Final Exam (Section C ) INSTRUCTIONS: Fill, tear and return the bottom strip of the front page with your scantron. Seperately, return back rest of the exam sheets. Use a #2 pencil to fill your scantron. Write your code number and bubble it in under ““EXAM NUMBER””. Bubble in the exam version (see letter A--H at bottom of page) in your scantron under ““TEST VERSION””. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A boat, whose speed in still water is 2.70 m/s, must cross a 280m wide river and arrive at a point 120m upstream from where it starts. To do so the pilot must head the boat at a 45 o upstream angle. What ʹs the speed of the riverʹs current? A) 2.07m/s B) 0.67 m/s C) 2.70 m/s D) - 1.10 m/s E) 1.10 m/s 2) A ball is shot from the top of a building with an initial velocity of 18 m/s at an angle θ = 42o above the horizontal. If a nearby building is the same height and 55 m away, how far below the top of the building will the ball strike the nearby building? A) 68 m B) 20 m C) 78 m D) 33 m E) 4 m --------Tear here and submit strip along with the scantron card. Follow TA instructions------Name____________________________________________Code-Number___________________ Final Exam (Section C) Version A‐1 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section C ) 3) A small block of mass m = 1 kg rests on the sloping side of a triangular block of mass M =10 kg. The angle θ=30o. The block M itself rests on a horizontal frictionless table. Assuming all surfaces are frictionless, what is the magnitude of the force F that must be applied to block M so that small block m remains in a fixed position relative to M? A) 6 N B) 108 N C) 56 N D) 17 N E) 62 N 4) A plumb bob suspended from a frame settles to a steady position as the frame slides down a frictionless inclined plane. What is the angle φ the plumb bob makes with the vertical during the slide if the angle θ =30o ? A) 45 o B) 30 o C) 60 o D) 15 o E) 7.5 o Final Exam (Section C ) Version A‐2 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section C ) 5) A small block of mass m =1.0 kg rests on the rough, sloping side of a triangular block of mass M =10.0 kg which itself rests on a horizontal frictionless table . If the angle θ = 30o and the coefficient of static friction is 0.50, what is the minimum force F applied to mass M that causes the small block m to start moving up the incline. ? A) 164 N B) 150 N C) 108 N D) 101 N E) 6.5 N 6) A small bead with a mass of 100g slides without friction along a semicircular wire with a radius of 10cm that rotates about a vertical axis at a rate of 2.0 revolutions per second. What is the value of θ for which the bead will remain stationary relative to the rotating wire? B) 70o C) 15o D) 30o E) 52o A) 45o Final Exam (Section C ) Version A‐3 7) A bullet of mass m = 1g embeds itself in a wooden block with mass M = 0.999 kg, which then compresses a spring (spring constant = 120N/m) by a distance of 0.050 m before coming to rest. The coefficient of kinetic friction between the block and table is 0.50. Whatʹs the initial speed of the bullet? A) 0.9 m/s B) 9 m/s C) 90 m/s D) 889 m/s E) 445 m/s 8) UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section C ) A toy car of mass M slides down a frictionless track that makes a circular loop of radius R at the bottom. The car starts from rest at a height H. What is the minimum value of H such that the car goes around the loop without falling off under force of gravity? A) 2.01 R B) (5/2) R C) 5R D) 2R E) 2(M/R) 9) A piece of thin wire of mass m and length 3a is bent into an equilateral triangle. Calculate the moment of inertia of the wire when it is rotating about an axis perpendicular to the plane of the triangle and passing through one of its vertices. 7 1 2 1 3 B) ma2 C) ma2 D) ma2 E) ma2 A) ma2 4 2 3 3 2 10) A billiard ball, of radius R = 3.0cm, that is initially at rest is given a sharp blow by a que stick The force is horizontal and is applied at a distance (2/3)R below the centerline. The speed v of the ball just after the blow is 3m/s. The surface between the ball and billiard table is frictionless. The angular speed of the ball just after the blow is ? (note: The moment of Inertia of a sphere of mass M and radius R for rotation about its CM is I = (2/5)MR2 ) A) 83 rad/s B) 166 rad/s C) 100 rad/s D) 50 rad/s E) 10 rad/s Final Exam (Section C ) Version A‐4 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section C ) 11) In the figure above, an 80 kg man is on a long rope ladder hanging from a balloon that has a total mass of 320 kg (including the basket passenger ). The balloon is initially stationary relative to the ground . When the man on the ladder begins to climb at 2.5 m/s relative to the ladder , whatʹs the velocity of the balloon relative to ground ? A) 0.63 m/s down B) Ballon will remain stationary ! C) 0.30 m/s down D) 0.63 m/s up E) 0.50 m/s down 12) A cart loaded with sand slides forward along a horizontal frictionless track. As the cart moves, sand trickles out at a constant rate through a hole in the bottom of the cart. The acceleration of the cart is: A) decreasing and in the forward direction B) zero C) constant and in the forward direction D) constant and in the backward direction E) increasing and in the forward direction 13) A block with mass M, on the end of a string, moves in a circle on a horizontal frictionless table as shown. As the string is slowly pulled through a small hole in the table: A) the angular momentum of the block remains contant B) the angular momentum of the block decreases C) the kinetic energy of the block remains constant D) the kinetic energy of the block decreases E) none of the above are true in this case Final Exam (Section C ) Version A‐5 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section C ) 14) A picture is to be hung from the ceiling by means of two wires. Order the following arrangements of the wires according to the tension force of wire B, from least to greatest: A) I, II, III B) II, I, III C) III, II, I D) I and II tie, then III E) all tie 15) In the crane set up above, the pivot at point B is frictionless, and the beam, of length 3.0 m, has mass 100kg. The rope makes an angle of 30 o with the horizontal and can withstand a tension of 10,000 N before breaking. If the arrangement is used to lift masses from the point shown on the beam, what is the maximum mass that can be so raised? A) 353 kg B) 4300 kg C) 1024 kg D) 512 kg E) 1112 kg 16) The weight of spaceman Spiff, solely due to the gravitational pull of planet X at its surface, is...
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This note was uploaded on 06/01/2009 for the course PHYS PHYS2A taught by Professor Hicks during the Fall '08 term at UCSD.

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