Physics for Scientists and Engineers: Foundations and Connections

15th Edition

ISBN: 9781305289963

Author: Debora M. Katz

Publisher: Cengage Custom Learning

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Textbook Question

Chapter 12, Problem 55PQ

A disk with a radius of 4.5 m has a 100-N force applied to its outer edge at two different angles (Fig. P12.55). The disk has a rotational inertia of 165 kg · m².

a. What is the magnitude of the torque applied to the disk in case 1?
b. What is the magnitude of the torque applied to the disk in case 2?
c. Assuming the force on the disk is constant in each case, what is the magnitude of the angular acceleration applied to the disk in each case?
d. Which case is a more effective way of spinning the disk? Describe which quantity you are using to determine “effectiveness” and why you chose that quantity.

Chapter 12, Problem 55PQ, A disk with a radius of 4.5 m has a 100-N force applied to its outer edge at two different angles

FIGURE P12.55

Definition Definition Rate of change of angular velocity. Angular acceleration indicates how fast the angular velocity changes over time. It is a vector quantity and has both magnitude and direction. Magnitude is represented by the length of the vector and direction is represented by the right-hand thumb rule. An angular acceleration vector will be always perpendicular to the plane of rotation. Angular acceleration is generally denoted by the Greek letter α and its SI unit is rad/s 2 .

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Chapter 12, Problem 54PQ

Chapter 12, Problem 56PQ

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Chapter 12 Solutions

Physics for Scientists and Engineers: Foundations and Connections

Ch. 12.1 - Figure 12.5 shows two rotating objects. Indicate...Ch. 12.2 - Prob. 12.2CE Ch. 12.2 - Prob. 12.3CE Ch. 12.2 - Prob. 12.4CE Ch. 12.2 - Prob. 12.5CE Ch. 12.5 - For each exercise shown in Figure 12.22, how does...Ch. 12 - Often, we model the Moon as a particle in a...Ch. 12 - Suppose a satellite orbits the Earth such that it...Ch. 12 - Prob. 3PQ Ch. 12 - Prob. 4PQ

Ch. 12 - A ceiling fan is rotating counterclockwise with a...Ch. 12 - As seen from above the Earths North Pole, the...Ch. 12 - A rotating objects angular position is given by...Ch. 12 - A rotating objects angular position is given by...Ch. 12 - Jupiter rotates about its axis once every 9 hours...Ch. 12 - Prob. 10PQ Ch. 12 - Prob. 11PQ Ch. 12 - Prob. 12PQ Ch. 12 - Prob. 13PQ Ch. 12 - Prob. 14PQ Ch. 12 - Prob. 15PQ Ch. 12 - A disk rolls up an inclined plane as shown in...Ch. 12 - Jeff, running outside to play, pushes on a...Ch. 12 - A potters wheel rotating at 240 rev/min is...Ch. 12 - Friction in an old clock causes it to lose 1...Ch. 12 - A wheel starts from rest and in 12.65 s is...Ch. 12 - Prob. 21PQ Ch. 12 - Starting from rest, a wheel reaches an angular...Ch. 12 - A potters wheel is rotating with an angular...Ch. 12 - The angular speed of a wheel is given by (t) =...Ch. 12 - Prob. 25PQ Ch. 12 - Prob. 26PQ Ch. 12 - An electric food processor comes with many...Ch. 12 - Prob. 28PQ Ch. 12 - A bicyclist is testing a new racing bike on a...Ch. 12 - Prob. 30PQ Ch. 12 - A disk is initially at rest. A penny is placed on...Ch. 12 - Prob. 32PQ Ch. 12 - Consider again the two wind turbines in Problem...Ch. 12 - Consider again the two wind turbines in Problem...Ch. 12 - In testing an automobile tire for proper...Ch. 12 - Prob. 36PQ Ch. 12 - A merry-go-round at a childrens park begins at...Ch. 12 - A wheel rotating at a constant rate of 1850...Ch. 12 - Why are doorknobs placed on the edge opposite the...Ch. 12 - Prob. 40PQ Ch. 12 - Prob. 41PQ Ch. 12 - Prob. 42PQ Ch. 12 - A wheel of inner radius r1 = 15.0 cm and outer...Ch. 12 - A uniform plank 6.0 m long rests on two supports,...Ch. 12 - Prob. 45PQ Ch. 12 - Prob. 46PQ Ch. 12 - Prob. 47PQ Ch. 12 - Prob. 48PQ Ch. 12 - Prob. 49PQ Ch. 12 - Prob. 50PQ Ch. 12 - Prob. 51PQ Ch. 12 - Given a vector A=4.5+4.5j and a vector B=4.5+4.5j,...Ch. 12 - A square plate with sides 2.0 m in length can...Ch. 12 - Prob. 54PQ Ch. 12 - A disk with a radius of 4.5 m has a 100-N force...Ch. 12 - Disc jockeys (DJs) use a turntable in applying...Ch. 12 - Prob. 57PQ Ch. 12 - Prob. 58PQ Ch. 12 - A wheel initially rotating at 85.0 rev/min...Ch. 12 - Prob. 60PQ Ch. 12 - A centrifuge used for training astronauts rotating...Ch. 12 - Problems 62 and 63 are paired. 62. C A disk is...Ch. 12 - Prob. 63PQ Ch. 12 - A potters wheel rotates with an angular...Ch. 12 - Prob. 65PQ Ch. 12 - Prob. 66PQ Ch. 12 - Prob. 67PQ Ch. 12 - Lara is running just outside the circumference of...Ch. 12 - The propeller of an aircraft accelerates from rest...Ch. 12 - A ball rolls to the left along a horizontal...Ch. 12 - Three forces are exerted on the disk shown in...Ch. 12 - Consider the disk in Problem 71. The disks outer...Ch. 12 - Prob. 73PQ Ch. 12 - Prob. 74PQ Ch. 12 - Prob. 75PQ Ch. 12 - Prob. 76PQ Ch. 12 - Prob. 77PQ Ch. 12 - Prob. 78PQ Ch. 12 - Prob. 79PQ Ch. 12 - Prob. 80PQ Ch. 12 - If the rod in Problem 79 is in equilibrium, what...Ch. 12 - As a compact disc (CD) spins clockwise as seen...Ch. 12 - A disk-shaped machine part has a diameter of 40.0...Ch. 12 - Prob. 84PQ

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Solution Summary: The author analyzes the torque applied to the disk in case 1 and the magnitude of the force applied.

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Chapter 12 Solutions