MT2 (s10)

# MT2 (s10) - Physics 121 Midterm 2. November 2, 2009 Exam...

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Physics 121 Midterm 2. November 2, 2009 Exam form 0 1 This is a closed book exam. Use your own formula sheet, 8½ x 11 inches, double sided, handwritten. You may only use your own calculator; NO SHARING. ANY manipulation of electronic equipment (I-Pod, cell phone, laptop computer, pager, etc.) other than your calculator is strictly prohibited, and will result in a zero on this exam. Answer all problems on the bubble scan sheet. Before you start, enter your name and student ID number on the answer sheet . This is exam form 0. Mark 0 on the first digit of birth day on the bubble scan sheet . (Do not fill in your birth date.) There are twenty questions, each of which carries equal weight. Question 1: (1 point) A block of mass m is pushed from the bottom to the top of a frictionless plane at constant speed. If d=2m, m=1kg and =30 o what is the amount of work done in pushing the block from the bottom to the top? (a) 1 J (b) 1.73 J (c) 16.99 J (d) 19.62 J (e) 9.81 J Question 2: (1 point) A motor is pulling a 500kg elevator upwards at 5m/s. How much mechanical power is the motor providing to the elevator? (a) 4,905 W (b) 6,250 W (c) 0 W (d) 2,500 W (e) 24,525 W

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Physics 121 Midterm 2. November 2, 2009 Exam form 0 2 Question 3: (1 point) A ball of mass 5kg is initially moving at 3 m/s and strikes a smaller ball of mass 2kg in a perfectly elastic collision. After the collision what is the velocity of the small ball? (a) -1.29 m/s (b) 1.29 m/s (c) 1.43 m/s (d) 4.29 m/s (e) -4.29 m/s Question 4: (1 point) A person is standing at the center of a giant disc of radius r which is initially rotating with an angular velocity . The person then starts to run radially outwards to the edge of the disc. When she reach the edge of the disc which one of the following statements is correct? (a) The angular velocity of the disc has decreased because the moment of inertia of the system has decreased (b) The angular velocity of the disc has increased because the moment of inertia of the system has increased (c) The angular velocity of the disc has increased because the moment of inertia of the system has decreased (d) The angular velocity of the disc is the same because momentum is conserved and the total mass of the system has not changed. (e) The angular velocity of the disc has decreased because the moment of inertia of the system has increased
Physics 121 Midterm 2. November 2, 2009 Exam form 0 3 Question 5: (1 point) Two cars collide at right angles in a perfectly inelastic collision and move off after the collision joined together with a velocity of v' at an angle of to the x axis. The one initially moving in the x direction has a mass of 1000kg and the one initially moving in the y direction has a mass of 800kg. If the initial velocity of the car moving in the x direction is v x = 15m/s and the initial velocity of the car moving in the

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## This note was uploaded on 03/06/2011 for the course PHY 121 taught by Professor Stephens during the Fall '08 term at SUNY Stony Brook.

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MT2 (s10) - Physics 121 Midterm 2. November 2, 2009 Exam...

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