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Show that, when a rigid body rotates about a fixed axis through O perpendicular to the body, the system of the momenta of its particles is equivalent to a single
Fig. P17.66
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- 2. Show that the gravitational self-energy (energy of assembly piecewise from infinity) 3GM? of a uniform sphere of mass M and radius R is U = - 5Rarrow_forwardA shaft carries four masses A,B,C and D of magnitude 220 kg, 320 kg, 420 kg and 220 kg respectively and revolving at radii 9cm, 7cm, 6 cm and 8cm in planes measured from A at 30cm, 45cm and 60cm. The angles between the cranks measured from A anticlockwise are 45°, 90° and 130°. The balancing masses are to be placed in planes X and Y. The distance between the planes A and X is 20cm, between X and Y is 50cm. If the balancing masses revolve at a radius of 15cm, find their magnitudes and angular positions.arrow_forwardTwo identical giant flywheels are on 2 identical slopes at an angle alpha = 20 deg. One flywheel is rolling on its inside shaft of diameter d1 = 3 ft, and the second flywheel is rolling without slipping on its outside diameter d2 = 5 ft. They are both released from rest. The weight of the flywheel is W = 8 lbs Knowing that flywheel 1 attains a speed of v = 7.0 ft/s in t = [t] s, (if t doesn't show take any t between 5 and 10 sec) find the radius of gyration of the flywheels, following those steps: b. Find omega final c. Find the angular impulse at the point of contact between the shaft and the slope. d. Write the formula to find the final momentum. e. Solve for k, using the principle of angular impulse and momentumarrow_forward
- 1. Determine the kinetic energy of the system of Fig.3.16 at an arbitrary instant in terms of x, including the inertia effects of the springs. 2m ima k. m, No slip 81, E k, m, F77777arrow_forwardA shaft with 3 meters span between two bearings carries two masses of 120 g and 100 g acting at the extremities of the arms 40 mm and 50 mm long respectively. The planes in which these masses rotate are 1.5 m and 2.5 m respectively from the left end bearing supporting the shaft. The angle between the arms is 120°. The speed of rotation of the shaft is 200 r.p.m. If the masses are balanced by two counter-masses rotating with the shaft acting at radii of 0.3 m and placed at 0.5 m from each bearing centers, estimate the magnitude of the two balance masses and their orientation with respect to the X-axis, i.e. mass of 120 g.arrow_forward5. A shaft carries five masses A, B, C, D and E which revolve at the same radius in planes which are equidistant from one another. The magnitude of the masses in planes A, C and D are 50 kg, 40 kg and 80 kg respectively. The angle between A and C is 90° and that between C and D is 135º. Determine the magnitude of the masses in planes B and E and their positions to put the shaft in complete rotating balance.arrow_forward
- Question No.15: A shaft carries four masses A, B, C and D placed in parallel planes perpendicular to the shaft axis and in this order along the shaft. The masses of B and C are 353 N and 245 N respectively and both are assumed to be concentrated at a radius of 15 cm, while the masses in planes A and D are both at a radius of 20 cm. The angle between the radii of B and C is 100° and that between B and A is 190°, both angles being measured in the same sense. The planes containing A and B are 25 cm apart and those containing B and C are 50 cm apart. If the shaft is to be in complete dynamic balance, determine i) Masses of A and D ii) distance between the planes containing C and D iii) angular position of the mass D.arrow_forwardLocate mass A at 35 mm from support X. 4.4. Locate mass B at 96.5 mm from support X. 4.5. Locate mass C at 122.7 mm from support X. 4.6. Position mass A at zero degrees and D at 90o from A. 4.7. Rotate the shaft by hand and release it. As the shaft is released masses should remain in any angular position. 4.8. Change the angular position of masses B and D till the shaft is statically balanced. 4.9. Rotate the shaft with the motor at high speed and notice the reaction of the system. High vibration and noise indicate that the system is out of balance. 4.10. Change the position of the mass D till the system is dynamically balanced.arrow_forward5) In ice figure skating, a couple execute a “top” (see picture). The centre of mass of the woman (58 kg) is situated 1.3 m from the axis of rotation which is vertical and passes through the centre of mass of the man (85 kg). They are spinning at a constant angular velocity equal to 3.1415 rad/s and the man and woman have moments of inertia, about their own centres of mass, equal to 1.6 and 2.5 kg.m2 respectively. Then the woman grabs the neck of the man. At this point, her moment of inertia decreases to 1.4 kg.m2 and her body centre of gravity is 0.9 m from the axis of rotation. Determine the new angular velocity. Hints: This is a conservation of angular momentum problem, and needs the parallel axis theorem to determine moments of inertia about the axis of rotation. The skaters are moving as one body with one angular velocity, but they each have their own moments of inertia given relative to their own CoMs. For the man, that’s fine…the axis they’re rotating about passes through his…arrow_forward
- The flywheel of a punching machine has a moment of inertia of 216 kg-m^2. 1 point Knowing that the speed of the flywheel is 10 rad/s, which of the following is the kinetic energy? * 10.8 kJ O 13.3 kJ O 33.9 kJ 106.6 kJarrow_forwardA truck with four wheels, each 750 mm diameter, travels on rails round a curve of 75 m at a speed of 50 km/h. The total mass of the truck is 5 t and its centre of gravity is midway between the axles, 1.05 m above the rails and midway between them. Each pair of wheels is driven by a motor rotating in the opposite direction to the wheels and at four times the speed. The moment of inertia of each pair of wheels is 15 Kgm2. The rails lie on a horizontal plane and 1.45 m apart. Determine the load on each rail.arrow_forwardM Axis 28 Fig. 2 Question 2: Two identical spheres, each of mass M=100g and negligible radius, are fastened to opposite ends of a magnetic rod of negligible mass and length 10m. This system is initially at rest with the rod horizontal, as shown in fig.2, and is free to rotate about a frictionless, horizontal axis through the center of the rod and perpendicular to the plane of the page. A bird, of mass 3M, lands gently on the sphere on the left. Determine the torque about (a) the axis immediately after the bird lands on the sphere. (b) the bird lands. Determine the angular acceleration of the rod-spheres-birds system immediately after (c) iron ball with mass 200g is thrown towards the road from top and when it reaches the rod with velocity 50m/s, sticks to it at midpoint between axis and the sphere on the left. Find the angular speed of the system. Consider the system is initially at rest with the rod horizontal, as shown in fig.2. A smallarrow_forward
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