Exam 2 for General Physics 1 - Spring 2006 | PHYS 1110, Exams of Physics

Download Exam 2 for General Physics 1 - Spring 2006 | PHYS 1110 and more Exams Physics in PDF only on Docsity! PHYS 1110 Exam 2 NAME:______________________________ Spring 2006 E2.1 Second Midterm Student ID #__________________________________________________ Section number and/or TA Name:___________________________________ Please do not open the exam until you are asked to. • Your exam should have 7 pages, numbered E2.1 thru E2.7. • This exam consists of 15 multiple choice questions, worth 5 points each, and a long-answer problem worth 25 points, for a total of 100 points. • Write your answers in the space provided on each page for the written question. Use the back of the page if needed. Circle the correct letter for the multiple choice questions. SHOW YOUR WORK ON THE WRITTEN QUESTIONS. Full credit will be given only for the correct answer accompanied by your reasoning. PLEASE!! 1. Print your name on each page in the space provided. 2. Print your student Identification Number on the page above. 3. Bubble your name and ID on the bubble sheet provided. 4. Write the name of your TA neatly in the big blank space at the bottom of the bubble sheet. Our TA's names are Scott Barbarow, Eszter Horanyi, Jason Pawlowski, Mike Shefferstein, Aaron Svoboda and Chandra Turpen. We recommend: Don’t waste time erasing mistakes on the written problems. Just put a line through defective reasoning. Ask for more paper if needed. At the end of the exam, check that you have completed all the questions. By handing in this exam, you agree to the following statement: "On my honor, as a University of Colorado Student, I have neither given nor received unauthorized assistance on this work" Signature______________________________________________ Possibly useful information: On any problems involving gravity, use g=10 m/s2! As always, neglect friction or air resistance (unless otherwise clearly stated) Good luck! PHYS 1110 Exam 2 NAME:______________________________ Spring 2006 E2.2 Second Midterm Circle the closest answer and Bubble in questions 1-15 ON YOUR BUBBLE SHEET! The following three questions refer to this situation: Two masses, a 10 kg mass and a 1 kg mass, start from rest and are acted on by the same constant net force for the same period of time. 1) The ratio of the acceleration of the heavy mass to the acceleration of the lighter mass, a10kg/a1kg, while the force acts is: (A) 10 (B) 1 (C) 0.1 (D) 0.01 (E) 100 2) After the force has stopped acting, the ratio of the speed of the heavy mass to the speed of the lighter mass, v10kg/v1kg, is: (A) 10 (B) 1 (C) 0.1 (D) 0.01 (E) 100 3) After the force has stopped acting, the ratio of the momentum of the heavy mass to the momentum of the lighter mass, p10kg/p1kg, is: (A) 10 (B) 1 (C) 0.1 (D) 0.01 (E) 100 4) A horse pulls a wagon at constant speed. Which of the following statements is CORRECT? (A) The force of gravity and the normal force on the horse are equal by Newton's 3rd Law. (B) The force of the wagon on the horse and the force of the horse on wagon are equal by Newton's 2nd Law. (C) There is a net force on the wagon to keep it moving. (D) Neither the horse nor the wagon is acted on by a net force. (E) The friction force of the wagon on the ground must exceed the friction force of the horse on the ground. 5) A 21 kg box must be slid across the floor. If the coefficient of static friction between the box and floor is 0.37, what is the minimum force needed to start the box moving from rest? (A) 78 N (B) 210 N (C) 7.8 N (D) 21 N (E) 106 N 6) A 30 kg block slides down a frictionless ramp that is tipped up at a 39 degree angle above the horizontal. The acceleration of the block is equal to: (A) 10 m/s2 (B) 7.8 m/s2 (C) 6.3 m/s2 (D) 189 m/s2 (E) 234 m/s2 PHYS 1110 Exam 2 NAME:______________________________ Spring 2006 E2.5 Second Midterm IMPORTANT !! Student Number__________________ Your TA's name (see front of exam if you forget) TA ______________________ 1) Three blocks, Blocks A, B, and C are being pushed across a frictionless table by a force, Fext, which exerts a constant horizontal force. Block A has mass, m, Block B has mass, 4m, and Block C has mass, 2m. Block A m Block B 4m Block C 2m Fext a) Draw separate free-body diagrams for each of the three blocks. Label your forces to make clear: i) The object on which the force is exerted, ii) the object exerting the forces, iii) The type of force (Normal, friction, gravitational, etc.) [5 pts] b) Draw vectors that represent the net force on each block. Draw the vectors with the correct relative magnitude. Explain how you knew to draw the net force vectors as you did.[5 pts] c) Suppose the mass of block B were halved (reduced to 2m, the other blocks left unchanged), and the external force pushes with the same force as before..[5 pts] i) Would the magnitude of the acceleration of block A (circle one) increase, decrease, or remain the same? Explain: ii) Would the magnitude of the net force of block A (circle one) increase, decrease, or remain the same? Explain: PHYS 1110 Exam 2 NAME:______________________________ Spring 2006 E2.6 Second Midterm 2) Two air track gliders are arranged on a level, frictionless track as shown. An experiment is conducted in which glider A is launched toward the stationary glider M. After the collision, glider A has reversed direction. In a second experiment, glider M is replaced by glider N, which has the same mass as glider M. Glider A is launched toward the stationary glider N with the same initial speed as in experiment 1. After the collision, glider A is at rest. The mass of glider M is five times that of glider A. (mM = 5mA, mM = mN) a) Draw separate arrows representing the direction of the change in velocity vector of glider A in experiments 1 and 2 [2pts] Direction of change in velocity vector for glider A in experiment 1 Direction of change in velocity vector for glider A in experiment 2 Is the magnitude of the change in velocity of glider A in experiment 1 (circle one): Greater than, less than, or equal to that in experiment 2? Explain: [3pts] b) After the collisions, is the speed of glider M (circle one) greater than, less than, or equal to the speed of glider N? If the speed of either glider is zero, state that explicitly. Explain: [5 pts]