Chapter 7:

13. To throw a discus, the thrower holds it with a fully outstretched arm. Starting from rest, he begins to turn with a constant angular acceleration, releasing the discus after making one complete revolution. The diameter of the circle in which the discus moves is about 1.8 m. If the thrower takes 1.0 s to complete one revolution, starting from rest, what will be the speed of the discus at release?

15. A computer hard disk starts from rest, then speeds up with an angular acceleration of 190rad/s2 until it reaches its final angular speed of 7200 rpm. How many revolutions has the disk made 10.0 s after it starts up?

29. What is the net torque on the bar shown in Figure P7.29, about the axis indicated by the dot? https://plus.pearson.com/epub/bronte/BRNT-DYHZY39USIJ/v29/OPS/images/5b5a04d4230798e945347b0343fe910c.jpeg

41. A solid cylinder with a radius of 4.0 cm has the same mass as a solid sphere of radius R. If the cylinder and sphere have the same moment of inertia about their centers, what is the sphere's radius?

43. A bicycle rim has a diameter of 0.65 m and a moment of inertia, measured about its center, of 0.19 kgm2. What is the mass of the rim?

Chapter 8:

7. A vendor hangs an 8.0 kg sign in front of his shop with a cable held away from the building by a lightweight pole. The pole is free to pivot about the end where it touches the wall, as shown in Figure P8.7. What is the tension in the cable?

https://plus.pearson.com/epub/bronte/BRNT-DYHZY39USIJ/v29/OPS/images/5780374743dcf8cb1955eeb6f433b8a6.jpeg

chapter 9:

43. Ice skaters often end their performances with spin turns, where they spin very fast about their center of mass with their arms folded in and legs together. Upon ending, their arms extend outward, proclaiming their finish. Not quite as noticeably, one leg goes out as well. Suppose that the moment of inertia of a skater with arms out and one leg extended is 3.2kgm2 and for arms and legs in is 0.80kgm2. If she starts out spinning at 5.0rev/s, what is her angular speed (in rev/s) when her arms and one leg open outward?

45. What is the angular momentum of the moon around the earth? The moon's mass is 7.41022kg and it orbits 3.810^8m from the earth.

chapter 10:

17. The turntable in a microwave oven has a moment of inertia of 0.040kgm2 and rotates continuously, making a complete revolution every 4.0 s. What is its kinetic energy?

19. An energy storage system based on a flywheel (a rotating disk) can store a maximum of 4.0 MJ when the flywheel is rotating at 20,000 revolutions per minute. What is the moment of inertia of the flywheel?