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For the disk of Prob. 18.99, determine (a) the couple M1j that should be applied to arm ABC to give it an angular acceleration
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Vector Mechanics For Engineers
- A 2.5-kg homogeneous disk of radius 80 mm rotates at the constant rate ω1 = 50 rad/s with respect to arm ABC, which is welded to a shaft DCE. Knowing that at the instant shown, shaft DCE has an angular velocity w2 = (12 rad/s)k and an angular acceleration a2= = (8 rad/s2)k, determine (a) the couple that must be applied to shaft DCE to produce that acceleration, (b) the corresponding dynamic reactions at D and E.arrow_forwardThe 10-oz disk shown spins at the rate w1= 750 rpm, while axle AB rotates as shown with an angular velocity w2 of magnitude 6 rad/s. Determine the dynamic reactions at A and B.arrow_forwardA stationary horizontal plate is attached to the ceiling by means ofa fixed vertical tube. A wheel of radius aa and mass mm is mounted on a light axle ACAC that is attached by means of a clevis at AA to a rod ABAB fitted inside the vertical tube. The rod ABAB is made to rotate with a constant angular velocity ΩΩ causing the wheel to roll on the lower face of the stationary plate. Determine the minimum angular velocity ΩΩ for which contact is maintained between the wheel and the plate. Consider the particular cases ( aa ) when the mass of the wheel is concentrated in the rim, (b) when the wheel is equivalent to a thin disk of radius aa also extend the problem using Kinematic and Kinetic analysisarrow_forward
- 4. Each of the gears A and B has a mass of 2.4 kg and a radius of gyration of 60 mm, while gear C has a mass of 12 kg and a radius of gyration of 150 mm. A couple M of constant magnitude 10 Nm is applied to gear C. Determine (a) the number of revolutions of gear C required for its angular velocity to increase from 100 to 450 rpm, (b) the corresponding tangential force acting on gear A. В S0 mm, S0 mm 200 mm. Marrow_forwardThe essential structure of a certain type of aircraft turn indicator is shown. Each spring has a constant of 500 N/m, and the 200-g uniform disk of 40-mm radius spins at the rate of 10 000 rpm. The springs are stretched and exert equal vertical forces on yoke AB when the airplane is traveling in a straight path. Determine the angle through which the yoke will rotate when the pilot executes a horizontal turn of 750-m radius to the right at a speed of 800 km/h. Indicate whether point A will move up or down.arrow_forwardConsider the mechanism shown. Members PQ and QR are joined by a hinge at Q. End P of member PQ is pin-supported and end R of member QR is constrained to move along a horizontal surface. Member PQ rotates clockwise at a constant rate of 12 rad/s. Member QR rotates counterclockwise at a rate of 3.84 rad/s. Which of the following gives the closest value to the magnitude of the angular acceleration of rod QR? 9.16, 6.18, 1.609, 35.2 rad/s^2?? Which of the following gives the closest value to the magnitude of the acceleration of point R? 3.13, 9.89, 10.28, 12.88 m/s^2??arrow_forward
- A homogeneous disk of mass m = 5 kg rotates at the constant rate w1 = 8 rad/s with respect to the bent axle ABC, which itself rotates at the constant rate w2, = 3 rad/s about the y axis. Determine the angular momentum HC of the disk about its center C.arrow_forwardThe wheel W of radius R = 1.4 m rolls without slip on a horizontal surface.A bar AB of length L = 3.7 m is pin-connected to the center of the wheel and to a sliderA constrained to move along a vertical guide. Point C is the bar’s midpoint. Determinethe general relation expressing the acceleration of the slider A as a function of θ, L, R,the angular velocity of the wheel αW , and the angular acceleration of the wheel ωW .arrow_forwardQ3. Two identical slender rods AB and BC are welded together to form an L-shaped assembly. The assembly is pressed against a spring at D and released from the position shown. Knowing that the maximum angle of rotation of the assembly in its subsequent motion is 90° counterclockwise, determine the magnitude of the angular velocity of the assembly as it passes through the position where rod AB forms an angle of 30° with the horizontal. h D B 1 0.4 m 0.4 marrow_forward
- Gear A weighs 1 lb and has a radius of gyration of 1.3 in.; gear B weighs 6 lb and has a radius of gyration of 3 in.; gear C weighs 9 lb and has a radius of gyration of 4.3 in. Knowing a couple M of constant magnitude of 40 lb-in. is applied to gear A, determine (a) the angular acceleration of gear C, (b) the tangential force that gear B exerts on gear C. M A 2 in. 2 in. borg J 4 in. B 6 in. с w ណarrow_forwardIf the earth were a sphere, the gravitational attraction of the sun, moon, and planets would at all times be equivalent to a single force R acting at the mass center of the earth. However, the earth is actually an oblate spheroid and the gravitational system acting on the earth is equivalent to a force R and a couple M. Knowing that the effect of the couple M is to cause the axis of the earth to precess about the axis GA at the rate of one revolution in 25 800 years, determine the average magnitude of the couple M applied to the earth. Assume that the average density of the earth is 5.51 g/cm 3 , that the average radius of the earth is 6370 km, and that ( Note: This forced precession is known as the precession of the equinoxes and is not to be confused with the free precession discussed in Prob. 18.123.)arrow_forwardEach of the gears A and B has a mass of 675 g and a radius of gyration of 40 mm, while gear C has a mass of 3.6 kg and a radius of gyration of 100 mm. Assume that kinetic friction in the bearings of gears A, B C produces couples of constant magnitude 0.15 N.m, 0.15 N.m, 0.3 N.m, respectively. Knowing that the initial angular velocity of gear C is 2000 rpm, determine the time required for the system to come to rest.arrow_forward
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