Graded Exam #2

Question 4 Correct 6.00 points out of 6.00 Question 5 Correct 6.00 points out of 6.00 On game shows, contestants are sometimes asked to spin large wheels. On a certain show, a contestant grabs the edge of a wheel and spins it from rest to an angular speed of 1.24 rad/s. If the radius of the wheel is 1.70 m and the contestant applies a constant force of 62N to the wheel for 0.50 s, what is the moment of inertia of the wheel? Assume that the contestant generates a maximum amount of torque. Select one: a. 42 N ⋅ m b. 84 N ⋅ m c. 110 N ⋅ m d. 170 N ⋅ m A truck that weighs 1000 N moves at 5 . 89 m /s when it hits another vehicle in an elastic collision. The second vehicle, weighing 981 N, was stationary but free to move. Find the final velocity of the second vehicle after the collision. Select one: a. v = 29 . 2 m /s b. v = 5 . 95 m /s c. v = 0 . 0583 m /s d. v = 58 . 3 m /s 2 2 2 2 2 f 2 f 2 f 2 f My Account 0

Question 11 Correct 6.00 points out of 6.00 Question 12 Correct 6.00 points out of 6.00 A gust of wind has caught the hinged trap door to a cellar and is holding it open. The door is square, with a side length of 1 . 25 m. The wind effectively applies a horizontal force of 85 N to the center of the door. If the rope holding the door against the wind is at a 45° angle, what is the tension in that rope? Select one: a. 120 N b. 60 N c. 43 N d. 30 N A surveillance plane weighing 1 . 91 × 10 N is flying horizontally at a velocity of 59 . 4 m /s due west in thick clouds. Suddenly the plane is struck a glancing blow from another plane. Before impact, this smaller plane weighing 9 . 74 × 10 N was traveling at 114 m /s due northwest at constant altitude. Immediately after impact, the second plane is knocked of course to a heading of 89 . 8 m /s at 35 . 2° north of west. Which of the following is the velocity of the surveillance plane after the collision? Select one: a. 61 . 1 m /s at 13 . 9° north of west b. 64 . 8 m /s at 12 . 8° north of west c. 61 . 1 m /s at 13 . 1° north of west d. 64 . 8 m /s at 13 . 1° north of west 4 3 My Account 0

Question 17 Correct 6.00 points out of 6.00 The formula for the precessional angular velocity of a top, , applies when the top is spinning at any angle from vertical, as long as b is the distance from the bottom tip of the top to the top's center of mass. A certain top can be modeled as a very thin rod with a uniform disk at its middle, as shown. The rod has mass and length z, and the disk has mass and radius r. The top is spun with an angular velocity , and its axis is at an angle from vertical. What is the linear velocity of the top end of the rod due to the top's precession? The moment of inertia of a uniform disk is . Select one: a. b. c. d. = dϕ dt mgb Iω m rod m disk ω θ I = M 1 2 R 2 ( + ) g sinθ m rod m disk z 2 2 ω m disk r 2 ( + ) g sinθ m rod m disk z 2 ω m disk r 2 g sinθ z 2 ω r 2 ( + ) g m rod m disk z 2 ω m disk r 2 My Account 0

Question 22 Correct 6.00 points out of 6.00 Question 23 Correct 6.00 points out of 6.00 Question 24 Incorrect 0.00 points out of 6.00 A 309 g glass rolls down an incline and onto a horizontal platform where it hits a beverage can that is laying at rest on its side. The top of the incline is 11 . 0 cm above the horizontal platform. The beverage can is initially at rest and weighs 7 . 35 N. Which of following is the final velocity of the glass? Select one: a. 0 . 612 m /s b. −5 . 83 m /s c. −1 . 35 m /s d. −0 . 612 m /s Which of the following physical quantities can be negative? Select one: a. kinetic energy b. potential energy c. both kinetic and potential energy Why is the kinetic energy of a spinning wheel not zero when its center of mass is not moving? Select one: a. The center of mass is spinning. b. The atomic motion of the center of mass is not zero. c. The potential energy of the wheel is not zero. d. The particles not at the center of mass are moving. My Account 0