What if two children push a swing at the same time? Would the swing go higher? Yes, together their force would be more. It is common for forces to be combined. Most objects on Earth have at least two forces acting on them. Do you know what one of them is? Of course, that force is gravity. How many forces do you have on you right now? Gravity pulls you down toward the center of Earth. Your legs exert a downward force. They hold you up against the pull of gravity. Consider the example in Figure 1.3. A book is resting on a table. Gravity pulls the book downward. It has a force of 20 newtons. At the same time, the table pushes the book upward. Its force is also 20 newtons. The table opposes the pull of gravity.

Question: "Give two examples of combined forces action on an object"

Answer: "A table pushes up on a book on a table, and gravity pulls down"

Response: yes

Static electricity is like a teeter-totter. What happens if a teeter-totter is balanced? Correct! It does not move. What about when its not balanced? Yes, it will now begin to move. Charges move when they are not balanced. Charges can build up by friction. Maybe you rub your feet on a wool mat or carpet. Rubber soled shoes readily gain charges. The wool carpet easily gives up charges. The two items become unbalanced. One item has a positive charge. The other has a negative charge. The difference in charge is called static electricity. Just like the teeter-totter, something is going to move. Positive charges build up on the mat. Negative charges build up on you.

Question: "What happens if a teeter-totter is balanced?"

Answer: "It will move"

Response: no

When American 11 struck the World Trade Center at 8:46, no one in the White House or traveling with the President knew that it had been hijacked. While that information circulated within the FAA, we found no evidence that the hijacking was reported to any other agency in Washington before 8:46. Most federal agencies learned about the crash in New York from CNN. Within the FAA, the administrator, Jane Garvey, and her acting deputy, Monte Belger, had not been told of a confirmed hijacking before they learned from television that a plane had crashed. Others in the agency were aware of it, as we explained earlier in this chapter. Inside the National Military Command Center, the deputy director of operations and his assistant began notifying senior Pentagon officials of the incident. At about 9:00, the senior NMCC operations officer reached out to the FAA operations center for information. Although the NMCC was advised of the hijacking of American 11, the scrambling of jets was not discussed. In Sarasota, Florida, the presidential motorcade was arriving at the Emma E. Booker Elementary School, where President Bush was to read to a class and talk about education. White House Chief of Staff Andrew Card told us he was standing with the President outside the classroom when Senior Advisor to the President Karl Rove first informed them that a small, twin-engine plane had crashed into the World Trade Center. The President's reaction was that the incident must have been caused by pilot error. At 8:55, before entering the classroom, the President spoke to National Security Advisor Condoleezza Rice, who was at the White House. She recalled first telling the President it was a twin-engine aircraft-and then a commercial aircraft-that had struck the World Trade Center, adding "that's all we know right now, Mr. President." At the White House, Vice President Dick Cheney had just sat down for a meeting when his assistant told him to turn on his television because a plane had struck the NorthTower of the World Trade Center. The Vice President was wondering "How the hell could a plane hit the World Trade Center" when he saw the second aircraft strike the South Tower. Elsewhere in the White House, a series of 9:00 meetings was about to begin. In the absence of information that the crash was anything other than an accident, the White House staff monitored the news as they went ahead with their regular schedules.

Question: "Who was standing next to the president when his reaction was that the crash of American 11 must be pilot error?"

Answer: "New York"

Response: no

Ratners Group PLC, a fast-growing, acquisition-minded London-based jeweler, raised its price for Seattle-based specialty jeweler Weisfield's Inc. to $57.50 a share, or $62.1 million, from $50 a share, or $55 million, after another concern said it would be prepared to outbid Ratners's initial offer. The other concern wasn't identified. Ratners's chairman, Gerald Ratner, said the deal remains of "substantial benefit to Ratners." In London at mid-afternoon yesterday, Ratners's shares were up 2 pence (1.26 cents), at 260 pence ($1.64). The sweetened offer has acceptances from more than 50% of Weisfield's shareholders, and it is scheduled for completion by Dec. 10. The acquisition of 87-store Weisfield's raises Ratners's U.S. presence to 450 stores. About 30% of Ratners's profit already is derived from the U.S.

Question: "Was the increased share price a good or bad deal for Ratners Group PLC?"

Answer: "It was not a good deal as it ensured that the other concern's offer would not be accepted"

Response:
no