final2 - 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 B) 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 girl wishes to swim across a river to a point directly opposite as shown. She can swim at 2m/s in still water and the river is flowing at 1m/s. At what angle θ with respect to the line joining the starting and finishing points should she swim? A) 90o 2) B) 30 o C) 45 o D) 63o E) 60o A rock is kicked horizontally at 15 m/s from a hill with a 45 o slope. How long does it take the rock to hit the ground ? A) 8.0 s B) 2.6 s C) 3.1 s D) 10.0 s E) 7.5 s --------Tear here and submit strip along with the scantron card. Follow TA instructions------Name____________________________________________Code-Number___________________ Final Exam (Section B) Version A‐1 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section B) 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) 17 N B) 62 N C) 108 N D) 6 N E) 56 N 4) Francesca dangles her watch from a thin piece of string while the car she is in starts from rest with a constant accelaration. After 16s , what is the speed of the car if the string makes an angle of 25 o with respect to the vertical at that time. D) 73 m/s E) 1480 m/s A) 23 m/s B) 250 m/s C) 900 m/s Final Exam (Section A) Version A‐2 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section B) 5) A 4.0 kg block is stacked on top of a 12 kg block which is accelerating along a horizontal table at a = 5.2 m/s2 . What minimum coefficient of friction between the two blocks will prevent the 4.0 kg block from sliding off? A) 0.26 B) 0.43 C) 0.87 D) 0.77 E) 0.53 6) You are asked to design a curved section of roadway that meets the following conditions: When ice is on the road, and the coefficient of static friction between the road and rubber is 0.080, a car at rest must not slide into the adjacent ditch and a car traveling less than 60 km/h must not skid to the outside of the curve. Neglect the effects of air drag and rolling friction. For the maximum allowed bank angle, what is the minimum radius of curvature of the curved roadway that you recommend ? A) 3 m B) 64 m C) 0.32km D) 1.2 km E) 0.18 km 7) A pendulum consists of a mass M =10 kg hanging at the bottom end of a massless rod of length l=100 cm, which has a frictionless pivot at its top end. A mass m =1kg, moving as shown with velocity v, impacts M and becomes embedded. What is the smallest value of v sufficient to cause the pendulum (with embedded mass m) to swing clear over the top of its arc? A) 69 m/s B) 63 m/s C) 630 m/s D) 690 m/s E) 31 m/s Final Exam (Section A) Version A‐3 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section B) 8) A 2.8 kg block slides over the smooth icy hill. The top of the hill is horizontal and 70m higher than its base. What minimum initial speed must the block have so that it will not fall into the canyon to the left of the 50m mesa ? E) 50 m/s A) 37 m/s B) 20 m/s C) 42 m/s D) 70 m/s 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. 2 3 1 1 7 B) ma2 C) ma2 D) ma2 E) ma2 A) ma2 3 2 3 2 4 10) A 0.16 kg billiard ball whose radius is 3.0cm is given a sharp blow by a cue stick. The applied force is horizontal and the line of action of the force passes through the center of the ball. The speed of the ball just after the blow is 4.0 m/s , and the coefficient of kinetic friction between the ball and the billiard table is 0.60. How long does the ball slide before it begins to roll without slipping? The moment of Inertia of a sphere with mass M and radius R for rotation about its CM is I = (2/5)MR2 . A) 67.0s B) 6.7 s C) 0.67s D) 0.19s E) 1.9s Final Exam (Section A) Version A‐4 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section B) 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) Ballon will remain stationary ! B) 0.63 m/s down C) 0.63 m/s up D) 0.30 m/s down 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) constant and in the forward direction B) decreasing and in the forward direction C) constant and in the backward direction D) zero E) increasing and in the forward direction 13) A phonograph record is dropped on to a freely spinning tunrtable. Then: A) neither angular momentum nor mechanical energy is conserved because of the frictional forces between record and the turntable. B) the frictional force between record and the turntable increases the total angular momentum C) the total angular momentum and kinetic energy remain constant D) the total angular momentum remains constant E) the frictional force between record and the turntable increases the total angular momentum Final Exam (Section A) Version A‐5 UCSD Physics 2A Winter 2008 Instructor : Vivek Sharma Final Exam (Section B) 14) A uniform plank is supported by two equal 120 - N forces at X and Y, as shown. The support at X is then moved to Z (half- way to the plank center). The supporting forces at Y and Z are then: A) FY = 240 N, F Z = 120N B) FY = 200 N, F Z = 40N C) FY = 40N, FZ = 200N D) FY = 160 N, F Z = 80N E) FY = 80N, FZ = 160N 15) A 1200 - N uniform boom is supported by a cable perpendicular to the boom as in figure . The boom is hinged at the bottom, and a 2000 - N weight hangs from its top. Find the vertical component of the reaction force exerted on the boom by the hinge. A) 1.33 kN down B) 2.58 kN up C) 1.47 kN up D) 1.33...
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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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