MCQOPTIONS
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MCQOPTIONS
This section includes 11 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering Mechanics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The flywheel A has a mass of 30 kg and a radius of gyration of kc = 95 mm. Disk B has a mass of 25 kg, is pinned at D, and is coupled to the flywheel using a belt which is subjected to a tension such that it does not slip at its contacting surfaces. If a motor supplies a counter-clockwise torque or twist to the flywheel, having a magnitude of M = (12t) N • m, where t is measured in seconds, determine the angular velocity of the disk 3 s after the motor is turned on. Initially, the flywheel is at rest. |
| A. | = 232 rad/s |
| B. | = 77.2 rad/s |
| C. | = 115.9 rad/s |
| D. | = 276 rad/s |
| Answer» D. = 276 rad/s | |
| 2. |
The square plate, where a = 0.75 ft, has a weight of 4 lb and is rotating on the smooth surface with a constant angular velocity of 1 = 10 rad/s. Determine the new angular velocity of the plate just after its corner strikes the peg P and the plate to rotate about P without rebounding. |
| A. | 2 = 6.67 rad/s |
| B. | 2 = 2.50 rad/s |
| C. | 2 = 10.00 rad/s |
| D. | 2 = 5.00 rad/s |
| Answer» C. 2 = 10.00 rad/s | |
| 3. |
A horizontal circular platform has a weight of 300 lb and a radius of gyration about the z axis passing through its center O of kz = 8 ft. The platform is free to rotate about the z axis and is initially at rest. A man, having a weight of 150 lb, begins to run along the edge in a circular path of radius 10 ft. If he has a speed of 4 ft/s and maintains this speed relative to the platform, compute the angular velocity of the platform. |
| A. | = 0.313 rad/s |
| B. | = 0.1754 rad/s |
| C. | = 0.225 rad/s |
| D. | = 1.429 rad/s |
| Answer» C. = 0.225 rad/s | |
| 4. |
A cord of negligible mass is wrapped around the outer surface of the 50-lb cylinder and its end is subjected to a constant horizontal force of P = 2 lb. If the cylinder rolls without slipping at A, determine its angular velocity in 4 s starting from rest. Neglect the thickness of the cord. |
| A. | = 34.3 rad/s |
| B. | = 17.17 rad/s |
| C. | = 8.59 rad/s |
| D. | = 11.45 rad/s |
| Answer» E. | |
| 5. |
The 50-kg cylinder has an angular velocity of 30 rad/s when it is brought into contact with the horizontal surface at C. If the coefficient of friction is c = 0.2, determine how long it takes for the cylinder to stop spinning. What force is developed at the pin A during this time? The axis of the cylinder is connected to two symmetrical links. (Only AB is shown.) For the computation, neglect the weight of the links. |
| A. | t = 1.529 s, A = 0 |
| B. | t = 3.06 s, A = 0 |
| C. | t = 1.529 s, A = 49.1 N |
| D. | t = 3.06 s, A = 49.1 N |
| Answer» D. t = 3.06 s, A = 49.1 N | |
| 6. |
The uniform pole has a mass of 15 kg and falls from rest when = 90° until it strikes the edge at A, = 60°. If the pole then begins to pivot about this point after contact, determine the pole's angular velocity just after the impact. Assume that the pole does not slip at B as it falls until it strikes A. |
| A. | 3 = 1.146 rad/s |
| B. | 3 = 0.537 rad/s |
| C. | 3 = 2.15 rad/s |
| D. | 3 = 1.528 rad/s |
| Answer» E. | |
| 7. |
A cord of negligible mass is wrapped around the outer surface of the 2-kg disk. If the disk is released from rest, determine its angular velocity in 3 s. |
| A. | = 183.9 rad/s |
| B. | = 735 rad/s |
| C. | = 245 rad/s |
| D. | = 263 rad/s |
| Answer» D. = 263 rad/s | |
| 8. |
The 12-kg disk has an angular velocity of = 20 rad/s. If the brake ABC is applied such that the magnitude of force P varies with time as shown, determine the time needed to stop the disk. The coefficient of friction at B is = 0.4. |
| A. | t = 13.00 s |
| B. | t = 7.00 s |
| C. | t = 8.92 s |
| D. | t = 5.08 s |
| Answer» E. | |
| 9. |
A constant torque or twist of M = 0.4N • m is applied to the center gear A. If the system starts from rest, determine the angular velocity of each of the three (equal) smaller gears in 3 s. The smaller gears (B) are pinned at their centers, and the mass and centroidal radii of gyration of the gears are given in the figure. |
| A. | B = 1975 rad/s |
| B. | B = 5830 rad/s |
| C. | B = 1520 rad/s |
| D. | B = 1022 rad/s |
| Answer» D. B = 1022 rad/s | |
| 10. |
Gear A has a weight of 1.5 lb, a radius of 0.2 ft, and a radius of gyration of ko = 0.13ft. The coefficient of friction between the gear rack B and the horizontal surface is = 0.3. If the rack has a weight of 0.8 lb and is initially sliding to the left with a velocity of (vB)2 = 8 ft/s to the left. Neglect friction between the rack and the gear and assume that the gear exerts only a horizontal force on the rack. |
| A. | M = 0.01425 lb-ft |
| B. | M = 0.00630 lb-ft |
| C. | M = 0.0622 lb-ft |
| D. | M = 0.0560 lb-ft |
| Answer» D. M = 0.0560 lb-ft | |
| 11. |
The uniform rod AB has a weight of 3 lb and is released from rest without rotating from the position shown. As it falls, the end A strikes a hook S, which provides a permanent connection. Determine the speed at which the other end B strikes the wall at C. |
| A. | vB4 = 14.74 ft/s |
| B. | vB4 = 20.3 ft/s |
| C. | vB4 = 22.0 ft/s |
| D. | vB4 = 12.69 ft/s |
| Answer» C. vB4 = 22.0 ft/s | |