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A simplified model of a washing machine is shown. A bundle of wet clothes forms a weight
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Check out a sample textbook solutionChapter 19 Solutions
Vector Mechanics For Engineers
- A 50 kg dough machine is mounted on an elastic support and opera to a speed of 1000 rpm. It has an unbalanced mass of 2 kg at an eccentric distance of 0.1 meter. If the damping factor ℶ = 0.2, determine: a) the constant of the support spring (without damping) which only transmits only up to 28% of the unbalanced force to the foundation, b) the resonant frequency in rpm, and c) the magnitude of the force transmitted with the complete suspension d) Illustrate using graphicsarrow_forwardA machine of mass 75 kg is mounted on springs and is fitted with a dashpot to damp out vibrations. There are three springs each of stiffness 10 N/mm and it is found that the amplitude of vibration diminishes from 38.4 mm to 6.4 mm in two complete oscillations. Assuming that the damping force varies as the velocity, determine : 1. the resistance of the dash-pot at unit velocity ; 2. the ratio of the frequency of the damped vibration to the frequency of the undamped vibration ; and 3. the periodic time of the damped vibration.arrow_forwardA machine of mass 30 kg is placed on an elastic foundation. A sinusoidal force of magnitude 28 N is applied to the machine. A frequency sweep reveals that the maximum steady-state amplitude of 1.3 mm occurs when the period of response is 0.22 sec. Determine the equivalent stiffness and damping ratio of the foundation.arrow_forward
- A 45-kg motor is bolted to a light horizontal beam that has a static deflection of 6 mm due to the weight of the motor. The unbalance of the motor is equivalent to a mass of 110 g located 75 mm from the axis of rotation. Knowing that the amplitude of the vibration of the motor is 0.25 mm at a speed of 300 rpm, determine (a) the damping factor c/cc(b) the coefficient of damping c.arrow_forwardA 2-kg block is supported by a spring with a constant of k= 128 N/m and a dashpot with a coefficient of viscous damping of c=0.6 N.s/m. The block is in equilibrium when it is struck from below by a hammer that imparts to the block an upward velocity of 0.4 m/s. Determine (a) the logarithmic decrement,(b) the maximum upward displacement of the block from equilibrium after two cycles.arrow_forwardA 1-kilogram mass is attached to a spring whose constant is 16 N/m, and the entire system is then submerged in a liquid that imparts a damping force numerically equal to 10 times the instantaneous velocity. Determine the equations of motion if the following is true. (Show a sketch of the problem) (a) the mass is initially released from rest from a point 1 meter below the equilibrium position (b) the mass is initially released from a point 1 meter below the equilibrium position with an upward velocity of 12 m/s (c) In parts a and b of the problem, determine whether the mass passes through the equilibrium position. In each case find the time at which the mass attains its extreme displacement from the equilibrium position. What is the position of the mass at this instant?arrow_forward
- An sdof system consists of mass 175 kg and a spring constant k 530 kn/m while testing the system a relative velocity of 0.3 m was observed on application of force of 450 n determine the damping ratioarrow_forwardAn 8-kg uniform disk of radius 200 mm is welded to a vertical shaft with a fixed end at B. The disk rotates through an angle of 3° when a static couple of magnitude 50N.m is applied to it. If the disk is acted upon by a periodic torsional couple of magnitude Tm=60N.m. determine the range of values of vf for which the amplitude of the vibration is less than the angle of rotation caused by a static couple of magnitude Tm.arrow_forwardShow that for a small value of the damping factor c/cc , the maximum amplitude of a forced vibration occurs when Wf= Wn and that the corresponding value of the magnification factor is ½ (c/c2).arrow_forward
- Two springs of constants K1 and K2 are connected in series to a block A that vibrates in simple harmonic motion with a period of 5 s. When the same two springs are connected in parallel to the same block, the block vibrates with a period of 2 s. Determine the ratio K1/K2 of the two spring constants.arrow_forwardA 360-lb motor is supported by springs of total constant 12.5 kips/ft. The unbalance of the rotor is equivalent to a 0.9-oz weight located 7.5 in. from the axis of rotation. Determine the range of speeds of the motor for which the amplitude of the fluctuating force exerted on the foundation is less than 5 lb.arrow_forwardThe block shown is depressed 1.2 in. from its equilibrium position and released. Knowing that after 10 cycles the maximum displacement of the block is 0.5 in., determine (a ) the damping factor c/c,(b) the value of the coefficient of viscous damping. (Hint: See Problems 19.129 and 19.130.)arrow_forward
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