PROBLEMS FROM SERWAY AND ADDITIONS TO FISHBANE PROBLEMS JUNE 14 - JUNE 20 FISHBANE - CHAPTER 8 81. Parts (b) and (d) are obvious, but you are expected to demonstrate the truth of your answer in each case. Note that the speed of the 3 kg object is given with respect to the SLED, not with respect to the ice. FISHBANE - CHAPTER 9 44. You must do problem 44 twice, once using Newton's Laws, and once using Conservation of Energy. SERWAY - CHAPTER 11 7. A car accelerates uniformly from rest and reaches a speed of 22 m/s in 9 s. The diameter of a tire is 58 cm. (a) Find the number of revolutions that a tire makes during this motion, assuming no slipping occurs. (b) What is the final rotational speed of a tire, in revolutions per second? 58. Two astronauts, each having a mass of 75 kg, are connected by a 10-m rope of negligible mass. They are isolated in space, orbiting their center of mass at speeds of 5 m/s. (a) Calculate the magnitude of the angular momentum of the system by treating the astronauts as particles. (b) Calculate the kinetic energy of the system. By pulling in on the rope, the astronauts shorten the distance between them to 5 m. (c) What is the new angular momentum of the system? (d) What are the astronauts' new speeds? (e) What is the new kinetic energy of the system? (f) How much work is done by the astronauts in shortening the rope? 65. An electric motor can accelerate a Ferris wheel of moment of inertia I = 20000 kg m^2 from rest to 10 rev/min in 12 s. When the motor is turned off, the Ferris wheel slows down from 10 to 8 rev/min in 10 s, due to frictional losses. Determine (a) the torque generated by the motor to bring the wheel to 10 rev/min and (b) the power needed to maintain the Ferris wheel's rotation speed of 10 rev/min.