Question 1 of 20 > 1 I \\ U'l l : View Policies Current Attempt in Progress Just after a motorcycle rides off the end of a ramp and launches into the air, its engine is turning counterclockwise at 7020 rev/min. The motorcycle rider forgets to throttle back, so the engine's angular speed increases to 13700 rev/min. As a result, the rest of the motorcycle (including the rider) begins to rotate clockwise about the engine at 3.50 rev/min. Calculate the ratio lE/lM of the moment of inertia of the engine to the moment of inertia of the rest of the motorcycle (and the rider). Ignore torques due to gravity and air resistance. ' 1 mm I c, ', . \\v ' ~ ' ' (A Q ~ (1)50 (0E1 Just after leavmg After engine speed ramp increases Number Units v Question 2 of 20 / 5 E View Policies Current Attempt in Progress Aat uniform circular disk (radius = 4.48 m, mass = 270 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a frictionless axis perpendicular to the center of the disk. A 60.0-kg person, standing 1.88 m from the axis, begins to run on the disk in a circular path and has a tangential speed of 3.70 m/s relative to the ground. Find the resulting angular speed (in rad/s) of the disk. Number n Units v Question 3 of 20 > - 15 .. . WN - View Policies Current Attempt in Progress A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 465-mile trip in a typical midsize car produces about 3.47 x 10" J of energy. How fast would a 14.3-kg flywheel with a radius of 0.484 m have to rotate to store this much energy? Give your answer in rev/min. Number i UnitsQuestion 4 of 20 - / 5 E View Policies Current Attempt in Progress A cylinder is rotating about an axis that passes through the center of each circular end piece. The cylinder has a radius of 0.0610 m, an angular speed of 84.0 rad/s, and a moment of inertia of 0.800 kg-mz. A brake shoe presses against the surface of the cylinder and applies a tangential frictional force to it. The frictional force reduces the angular speed of the cylinder by a factor of 7 during a time of 4.00 s. (3) Find the magnitude of the angular deceleration of the cylinder. (b) Find the magnitude of the force of friction applied by the brake shoe. (a) Number Units v (b) Number n Units v Question 5 of 20 / 5 E View Policies Current Attempt in Progress A particle is located at each corner of an imaginary cube. Each edge of the cube is 0.574 m long, and each particle has a mass of 0.537 kg. What is the moment of inertia of these particles with respect to an axis that lies along one edge of the cube? Number n Units v Question 6 of 20 _ ,r 5 E Current Attempt in Progress A person exerts a horizontal force F of 190 N in the test apparatus shown in the drawing. Neglect the weight of the forearm. (3} Draw the freebled).r diagram showing the forces that act on the person's forearm. [In] Find the horizontal force M {magnitude and direction] that his exor muscle exerts on his forearm. Elbow joint Step 1 Draw the free-body:r diagra m showing t he forces that act on the person's forearm. Use the checkboxes to Select the Correct vectors as instructed above. Move the vectors to the correct starting points and orient them in the correct direction as instructed. El F]: El f Key to Force Labels FE = Elbow force |:| FX CI M Fx = Spring force F = Apparatus force T = Tension f = Friction force M = Muscle force Draw free-body diagram here Question 7 of 20 - 15 E . . . View Policies Current Attempt in Progress A person is standing on a level floor. His head, upper torso, arms, and hands together weigh 463 N and have a center of gravity that is 1.13 m above the floor. His upper legs weigh 102 N and have a center of gravity that is 0.738 m above the floor. Finally, his lower legs and feet together weigh 95.5 N and have a center of gravity that is 0.216 m above the floor. Relative to the floor, find the location of the center of gravity for the entire body. X'1 X7 13 Number UnitsQuestion 8 of 20 / 5 View Policies Current Attempt in Progress Which one of the following statements describes the conditi0n(s) for which a rigid body is in equilibrium? O Each external torque may not be non-zero, but the sum of the torques must be zero. 0 Each external force may be non-zero, but the sum of the forces must be zero. O The sum of the externally applied forces must be zero, and the sum of the externally applied torques must be zero. 0 Only internal forces can be present. 0 Each external torque acting on the body must be zero. Question 9 of 20 / 5 E View Policies Current Attempt in Progress Five hockey pucks are sliding across frictionless ice. The drawing shows a top View of the pucks and the three forces that act on each one. The forces can have different magnitudes (F, 2F, or 3F), and can be applied at different points on the puck. Only one ofthe ve pucks could be in equilibrium. Which one? F F r F 3F 21-" F 2r F 21' (1) (2) (3) (4) (5) Question 10 onO _ ,r 5 ;= : Current Attempt in Progress To answer this question, first click here to View the associated video. The gure shows an overhead View of a large door that is free to pivot on a hinge along its left edge. Aforce F is applied to the door in four different ways. The magnitude ofthe force is the same in each case. In which case is the torque on the door the largest? A B Hm Hing Hing Hing ( Two forces are applied to a ship's wheel. The wheel is not rotating. Which ofthe following must be true? O The magnitude of the torque created by F. must be equal in magnitude to the torque created by F2. 0 The magnitude of the torque created by F. must be greater than the magnitude ofthe torque created by F2. 0 The magnitude of the torque created by F2 must be greater than the magnitude ofthe torque created by F. . O F] must be equal to F3. Question 11 of 20 > - 15 . . . WIN - View Policies Current Attempt in Progress A cylindrically shaped space station is rotating about the axis of the cylinder to create artificial gravity. The radius of the cylinder is 102 m. The moment of inertia of the station without people is 4.78 x 109 kg.m2. Suppose 245 people, with an average mass of 52.0 kg each, live on this station. As they move radially from the outer surface of the cylinder toward the axis, the angular speed of the station changes. What is the maximum relative change (A w/w) max in the station's angular speed due to the radial movement of the people? Number UnitsQuestion 12 of 20 - 15 . . . View Policies Current Attempt in Progress Two skaters, each of mass 40 kg, approach each other along parallel paths that are separated by a distance of 2 m. Both skaters have a speed of 10 m/s. The first skater carries a 2-m pole that may be considered massless. As he passes the pole, the second skater catches hold of the end. The two skaters then go around in a circle about the center of the pole. Top 10 m/s View 2 m pole 10 m/s What is their combined angular momentum about the center of the pole? O 2 kg . m2/s O 40 kg . m2/s O 80 kg . m2/s O 400 kg . m2/s O 800 kg . m2/sQuestion 13 of 20 - / 5 E View Policies Current Attempt in Progress A bowling ball encounters a 0.760-m vertical rise on the way back to the ball rack, as the drawing illustrates. Ignore frictional losses and assume that the mass of the ball is distributed uniformly. The translational speed of the ball is 6.76 m/s at the bottom of the rise. Find the translational speed at the top. Number a Units v Question 14 of 20 - 15 ... View Policies Current Attempt in Progress A 2.0-kg solid cylinder of radius 0.5 m rotates at a rate of 40 rad/s about its cylindrical axis. What power is required to bring the cylinder to rest in 10 s? O 40 W O 160 W O 200 W O 400 W O 20 WQuestion 15 of 20 _ / 5 3: View Policies Current Attempt in Progress The drawing shows two identical systems of objects; each consists of the same three small balls connected by massless rods. In both systems the axis is perpendicular to the page, but it is located at a different place, as shown. The same force of magnitude F is applied to the same ball in each system (see the drawing). The masses of the balls are m1 = 9.5 kg, m2 = 6.0 kg, and m3 = 7.7 kg. The magnitude of the force is F = 465 N. (a) For each of the two systems, determine the moment of inertia about the given axis of rotation. (b) Calculate the torque (magnitude and direction) acting on each system. ((1) Both systems start from rest, and the direction of the force moves with the system and always points along the 4.00-m rod. What is the angular velocity of each system after 5.76 s? System A System B Question 16 of 20 _ / 5 ;: View Policies Current Attempt in Progress The drawing shows a rectangular piece of wood. The forces applied to corners B and D have the same magnitude of 12 N and are directed parallel to the long and short sides of the rectangle. The long side of the rectangle is twice as long as the short side. An axis of rotation is shown perpendicular to the plane of the rectangle at its center. A third force (not shown in the drawing) is applied to corner A, directed along the short side of the rectangle (either toward B or away from B), such that the piece of wood is at equilibrium. Find the magnitude and direction of the force applied to corner A. \"1| :9. H