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QUIZ 4 Nota means none of the above. |
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| The sample quiz below is under construction. Please keep checking back often to see the entire thing before the real quiz tomorrow. |
| 1. A record on a DJ's turntable has a radius r of 6 inches. It rotates at 33 RPM. One particle (1) of dust is 2 inches from the center. Another dust particle (2) is 4 inches from the center. Which particle dust has the greatest linear speed v? |
| a. particle 1. |
| b. particle 2 |
| c. both have the same linear speed |
| d nota |
| 2. In the previous problem, which particle has the greatest angular speed? |
| a. particle 1. |
| b. particle 2 |
| c. both have the same angular speed |
| d nota |
| 3. In the previous problem, what is the ratio of the linear speed of particle 1 to the linear speed of particle 2 ? |
| a. 1 |
| b. 6/4 |
| c. 2 |
| d. 1/2 |
| e. nota |
| 4. What is the tangential speed of a passenger on a Ferris Wheel that has radius r = 10 m and rotates once in 2 seconds? |
| a. 6.28 m/s |
| b. 62.8 m/s |
| c. 3.14 m/s |
| d. 31.4 m/s |
| e. nota |
| 5. Which has the larger rotational inertia I? |
| a. A uniform stick about an axis at the end. |
| b. The same stick about an axis at the center of mass. |
| c. Nota |
| 6. To tighten a bolt, you push with a force of 60 N at the end of a wrench handle that is 0.50 m from the bolt axis. Assume the force is perpendicular to the wrench. What is the magnitude of the torque you are exerting? |
| a. 60 Nm |
| b. 20 N |
| c. 30 N |
| d. 30 Nm |
| e. nota |
| 7. In the previous problem, suppose you move your hand inward to be only 0.10 m from the bolt axis. What force should you exert to produce the same torque magnitude? Assume the force is perpendicular to the wrench. |
| a. 600 Nm |
| b. 300 N |
| c. 300 Nm |
| d. 600 N |
| e. nota |
| 8. In problem 6, suppose you exert a 60 N force that is not perpendicular to the wrench. The torque will |
| a. increase |
| b. decrease |
| c. remain the same |
| d. nota |
| 9. You are sitting at rest on a park bench. You observe a ladybug inside a can that your friend is whirling in a horizontal circle. In your reference frame, what force causes the bug to move in circle? |
| a. The weight of the can. |
| b. The gravitational force on the bug. |
| c. The normal force of the can on the bug's feet. |
| d. nota |
| 10. Consider the previous problem in the reference frame of the lady bug. In that frame, the bug is held to the bottom of the can by an apparent force that is |
| a. directed toward the center of the circular motion. |
| b. directed away from the center of the circular motion |
| c. directed tangent to the circle. |
| d. nota |