Problem: It is not enough to describe some objects by their location. We may also need to know its direction. For example, a wind blows a storm over your school. Where is that storm coming from? Where is it going? How can we describe a direction? The most common way is by using a compass. A compass is a device with a floating needle (Figure 2.1). The needle is a small magnet. The needle aligns itself with the Earth's magnetic field. The compass needle always points to magnetic north. If you have a compass and you find north. You can then know any other direction. See the directions, such as east, south, west, etc., on a compass rose. The Earth has two poles. It has a magnetic north pole. It also has a geographic north pole. These two poles are close to each other but not the exact same place.

Question: "How does the compass work?"

Answer: "The magnetic north pole will pull the magnet needle causing it to point north."

OPTIONS:
- no
- yes
Answer: yes

Problem: According to the radar reconstruction, American 77 reemerged as a primary target on Indianapolis Center radar scopes at 9:05, east of its last known position. The target remained in Indianapolis Center's airspace for another six minutes, then crossed into the western portion of Washington Center's airspace at 9:10. As Indianapolis Center continued searching for the aircraft, two managers and the controller responsible for American 77 looked to the west and southwest along the flight's projected path, not east-where the aircraft was now heading. Managers did not instruct other controllers at Indianapolis Center to turn on their primary radar coverage to join in the search for American 77. In sum, Indianapolis Center never saw Flight 77 turn around. By the time it reappeared in primary radar coverage, controllers had either stopped looking for the aircraft because they thought it had crashed or were looking toward the west. Although the Command Center learned Flight 77 was missing, neither it nor FAA headquarters issued an all points bulletin to surrounding centers to search for primary radar targets. American 77 traveled undetected for 36 minutes on a course heading due east for Washington, D.C. By 9:25, FAA's Herndon Command Center and FAA headquarters knew two aircraft had crashed into the World Trade Center. They knew American 77 was lost. At least some FAA officials in Boston Center and the New England Region knew that a hijacker on board American 11 had said "we have some planes." Concerns over the safety of other aircraft began to mount. A manager at the Herndon Command Center asked FAA headquarters if they wanted to order a "nationwide ground stop." While this was being discussed by executives at FAA headquarters, the Command Center ordered one at 9:25. The Command Center kept looking for American 77. At 9:21, it advised the Dulles terminal control facility, and Dulles urged its controllers to look for primary targets. At 9:32, they found one. Several of the Dulles controllers "observed a primary radar target tracking eastbound at a high rate of speed" and notified Reagan National Airport. FAA personnel at both Reagan National and Dulles airports notified the Secret Service.

Question: "What was one of the mistakes besides the air traffic control search that lead to America 77 flying for 36 min. undetected?"

Answer: "Looked in the wrong direction"

OPTIONS:
- no
- yes
Answer: yes

Problem: (CNN) -- Horror-meister, Stephen King calls George Pelecanos "perhaps the greatest living American crime writer." His stories are set in Pelecanos' hometown of Washington, D.C., but this is not the side of the U.S. capitol that you see portrayed on TV with white marble monuments, lawyers and lobbyists. Pelecanos is more interested in working families struggling to get by, the racial tensions in its ethnic neighborhoods and the low-lifes on the edges. His crime-writing peers call Pelecanos the "undisputed poet" of Washington's gritty side. The best-selling and award-winning author is out this week with his 17th and latest novel, "The Cut." It's the first in a new series featuring Iraq war veteran and private investigator Spero Lucas. When he's not working for a Washington defense attorney, Lucas recovers stolen property for a 40% cut. Now, a high-profile crime boss hires Lucas to find out who's been stealing from him, and it could turn out to be Lucas' biggest payday or an untimely end. While Pelecanos made his bones in the noir tradition, there's a definite "Western" feel to "The Cut." The new novel takes place in a morally gray and often violent world. It's peppered with pitch-perfect dialogue and captures the sights, sounds and taste of Washington in rich detail. In short, Pelecanos reads like the real deal. Pelecanos knows a thing or two about capturing the authenticity of urban America with an ethnically and socially diverse cast. In addition to his success as a novelist, Pelecanos is a producer and writer for HBO's New Orleans-set, "Treme." He was previously a producer and Emmy-nominated writer on the hit series "The Wire" and the miniseries "The Pacific." Read an excerpt from "The Cut" CNN recently spoke to Pelecanos about his new novel. The following is an edited transcript. CNN: Tell me more about your new character, Spero Lucas.

Question: "George Pelecanos has been involved as a writer and producer for which television shows?"

Answer: "Dancing with the Stars"

OPTIONS:
- no
- yes
Answer:
no