7. A 2.5-kg solid homogeneous ball is rolling without slipping at 6.0 meters per second to the right on a level surface. The diameter of the ball is 30 centimeters. What is the total kinetic energy of the ball? 8. A perfect spring is attached to a 5.91-kg cart that slides on a frictionless horizontal surface. as shown. The cart is displaced from its equilibrium position and released. The cart oscillates 39 cycles in 6.5 seconds. (a) Find the frequency of the oscillation. (b) Find the spring constant. 9. A 14.0-kg solid homogeneous disk of radius 0.600 m is rotating with an initial angular speed of 50.0 rad/s about a frictionless horizontal shaft. A 6.00-kg solid homogeneous disk of radius 0.400 m is initially al rest on the same shaft. The disks are pushed into contact. as shown. Because of surface friction, the two disks eventually attain a final common angular speed wp (a) Find the final common angular speed wy of the system. (b) In the collision of the two disks. kinetic energy is not conserved because nonconservative ( frictional) internal forces act during the contact. How much energy was lost to friction in the collision? Wo = 50.0 fad Before contact After contact 10. A 2.5-kilogram ball attached to a string of negligible mass travels along a horizontal circle of radius , as shown. The ball has a constant angular speed of 0.764 revolution per second. The length of the string is 1.25 meters. (a) Find the tension in the string. (b) Find the angle B. ysics by Saxon Copyright @ 1993 by Saxon Publishers, Inc. Reprod