2) The L-shaped object shown in the figure consists of three small masses 1 kg connected by extremely light rods. Assume that the masses shown are accurate to three significant figures. What is the moment of inertia of this object (a) about the x-axis, and (b) about the y-axis? 1.80 m 12kgx 3.30 mo 3) The L-shaped object shown in the figure consists of three small masses connected by thin uniform rods, each rod of mass 3.00 kg. Assume that the 1 kg 1 kg masses shown are accurate to three significant figures. What is the moment of inertia of this object (a) about the x-axis, and (b) about the y-axis? 1.80 m 2kg 3.30 m8) What is the kinetic energy of a 120-cm thin uniform rod with a mass of 450 g that is rotating about its center at 3.60 rad/s? A) 0.350 J B) 4.20 J C) 0.700 J D) 0.960 J E) 2. 10 J 9) The torque required to turn the crank on an ice cream maker is 4.50 N . m. How much work does it take to turn the crank through 300 full turns? A) 4240 J B) 8480 J C) 2120 J D) 1350 J E) 2700 J Angular Momentum 10) When is the angular momentum of a system constant? A) Only when its total kinetic energy is constant. B) Only when no net external force acts on the system. C) Only when the linear momentum and the energy are constant. D) Only when no net external torque acts on the system. E) Only when the moment of inertia is constant.11) A uniform, solid, cylindrical flywheel of radius 1.4 m and mass 15 kg rotates at 2.7 rad/s. What is the magnitude of the flywheel's angular momentum? A) 40 kg . m2/s B) 20 kg . m2/s C) 80 kg . m2/s D) 60 kg . m2/s 12) A uniform 135-g meter stick rotates about an axis perpendicular to the stick passing through its center with an angular speed of 3.50 rad/s. What is the magnitude of the angular momentum of the stick? A) 0.0394 kg . m2/s B) 0.473 kg . m2/s C) 0.0739 kg . m2/s D) 0.158 kg . m2/s E) 0.0236 kg . m2/s 13) A ballerina spins initially at 1.5 revis when her arms are extended. She then draws in her arms to her body and her moment of inertia becomes 0.88 kg . m2, and her angular speed increases to 4.0 rev/s. What was her initial moment of inertia?14) An ice skater has a moment of inertia of 5.0 kg . m2 when her arms are outstretched, and at this time she is spinning at 3.0 rev/s. If she pulls in her arms and decreases her moment of inertia to 2.0 kg . m2, how fast will she be spinning? A) 2.0 rev/s B) 3.3 rev/s C) 7.5 rev/s D) 10 rev/sA student sits on a pivoted stool while holding a pair of weights. The stool is ee to rotate about a vertical axis with negligible friction. The moment of inertia of student, weights, and stool is 2.25 kg.m2. The student is set in rotation with arms outstretched, making one complete turn every 1.26s, arms outstretched. 15} 1What is the initial angular speed of the system?I 16} As he rotates, he pulls the weights inward so that the new moment of inertia of the system (student, objects, and stool} becomes 1.30 kgmz. What is the new angular speed of the system? I?) Find the work done by the student on the system while pulling in the weights. {Ignore energy lost through dissipation in his muscles.) A student sits on a rotating stool holding two 3.0-kg objects. When his arms are extended horizontally, the objects are 1.0 m from the axis of rotation and he rotates with an angular speed of 0.15 radfs. The moment of inertia of the student plus stool is 3.0 1;ng and is assumed to be constant. The student then pulls in the objects horizontally to 0.30 m from the rotation axis. 13} Find the new angular speed of the student. 19} Find the kinetic energy of the student before and after the objects are pulled in. 20} Find the work done by the student on the system while pulling in the weights. {Ignore energy lost through dissipation in his muscles.)