10.9 -. The flywheel of an engine has moment of inertia 1.60 kg . m about its rotation axis. What constant torque is re- quired to bring it up to an angular speed of 400 rev/min in 8.00 s. starting from rest? 10.8 .. A uniform disk with mass 40.0 kg and radius 0.200 m is pivoted al its center about a horizontal, frictionless axle that is stationary. The disk is initially at rest. and then a constant force F = 30.0 N is applied tangent to the rim of the disk, (a) What is the magnitude v of the tangential velocity of a point on the rim of the disk after the disk has turned through 0.200 revolution? (b) What is the magnitude a of the resultant acceleration of a point on the rim of the disk after the disk has turned through 0.200 revolution? 10.12 . CP A stone is suspended from the free end of a wire that is wrapped around the outer rim of a pulley, similar to what is shown in Fig. 10.10. The pulley is a uniform disk with mass 10.0 kg and radius 30.0 cm and turns on frictionless bearings. You measure that the stone travels 12.6 m in the first 3.00 s starting from rest. Find (a) the mass of the stone and (b) the tension in the wire. 21) A uniform hollow spherical ball of mass 1.75 kg and radius 40.0 cm rolls without slipping up a ramp that rises at 30.0 above the horizontal. The speed of the ball at the base of the ramp is 2.63 m/s. While the ball is moving up the ramp, find (a) the acceleration (magnitude and direction) of its center of mass and (b) the friction force (magnitude and direction) acting on it due to the surface of the ramp. 9.33 as A wagon wheel is con- Figure E9.33 structed as shown in Fig. E9.33. The radius of the wheel is 0.300 m. and the rim has mass 1.40 kg. Each of the eight spokes that lie along a diameter and are 0.300 m long has mass 0.280 kg. What is the moment of inertia of the wheel about an axis through its center and perpen- dicular to the plane of the wheel? (Use Table 9.2.) 0.600 m