QUES: Take a look at this train in Figure 1.11. It looks very futuristic. What do you notice about it? Did you notice that the train has no wheels? How can a train have no wheels? It doesn't need wheels. It actually floats, or levitates, just above the track. Magnets enable the train to do this. This is not a normal train. This is a maglev train. The word maglev stands for magnetic levitation. Because it has no wheels, there is no friction. Some magnets hold the train up. Other magnets are used to move the train forward. This train can go very fast. It can reach speeds up to 480 kilometers (300 miles) per hour! Magnets are pretty cool. What exactly is a magnet? How is it able to exert such force?
Do you have any questions?
MY QUESTION: How does the train move?

QUES: In February 1998, the 40-year-old Saudi exile Usama Bin Laden and a fugitive Egyptian physician, Ayman al Zawahiri, arranged from their Afghan headquarters for an Arabic newspaper in London to publish what they termed a fatwa issued in the name of a "World Islamic Front." A fatwa is normally an interpretation of Islamic law by a respected Islamic authority, but neither Bin Laden, Zawahiri, nor the three others who signed this statement were scholars of Islamic law. Claiming that America had declared war against God and his messenger, they called for the murder of any American, anywhere on earth, as the "individual duty for every Muslim who can do it in any country in which it is possible to do it." Three months later, when interviewed in Afghanistan by ABC-TV, Bin Laden enlarged on these themes. He claimed it was more important for Muslims to kill Americans than to kill other infidels." It is far better for anyone to kill a single American soldier than to squander his efforts on other activities," he said. Asked whether he approved of terrorism and of attacks on civilians, he replied:"We believe that the worst thieves in the world today and the worst terrorists are the Americans. Nothing could stop you except perhaps retaliation in kind. We do not have to differentiate between military or civilian. As far as we are concerned, they are all targets." Note: Islamic names often do not follow the Western practice of the consistent use of surnames. Given the variety of names we mention, we chose to refer to individuals by the last word in the names by which they are known: Nawaf al Hazmi as Hazmi, for instance, omitting the article "al" that would be part of their name in their own societies. We generally make an exception for the more familiar English usage of "Bin" as part of a last name, as in Bin Laden. Further, there is no universally accepted way to transliterate Arabic words and names into English. We have relied on a mix of common sense, the sound of the name in Arabic, and common usage in source materials, the press, or government documents. When we quote from a source document, we use its transliteration, e.g.,"al Qida" instead of al Qaeda. Though novel for its open endorsement of indiscriminate killing, Bin Laden's 1998 declaration was only the latest in the long series of his public and private calls since 1992 that singled out the United States for attack. In August 1996, Bin Laden had issued his own self-styled fatwa calling on Muslims to drive American soldiers out of Saudi Arabia.
Do you have any questions?
MY QUESTION: Who said "It is far better for anyone to kill a single American soldier than to squander his efforts on other activities."

QUES: (CNN) -- A federal court jury in Florida convicted seven people of participating in a global child pornography trafficking enterprise, according to the Department of Justice. Jurors convicted the seven Wednesday of multiple counts of child exploitation, pornography and obstruction of justice. Members of the organization used Internet news groups to swap and share "illegal images and videos depicting prepubescent children, including toddlers, engaged in various sexual and sadistic acts," prosecutors said. An indictment filed in the case detailed interactions between group members as they swapped and commented on images. "My thanks to you and all the others that together make this the greatest group of pedos to ever gather in one place," Freeman wrote in response to one posting, according to the indictment. And a posting from Castleman, cited in the indictment, read, "Thanks to all for the wonderful material that has been posted." An Australian constable who infiltrated the group in August 2006 was among 50 witnesses testifying at trial. He told the jury that the group traded more than 400,000 images and videos of child sexual abuse before being dismantled by law enforcement, according to the Justice Department statement. Each defendant faces a sentence of 20 years to life in prison, fines and the possibility of supervised release for the rest of their lives, authorities said. The seven will be sentenced April 14. During the six-day trial, evidence showed the seven participated in what prosecutors called a "well-organized criminal enterprise whose purpose was to proliferate child sex abuse images to its membership during a two-year period." "This was a wide-scale, high-volume, international trafficking enterprise that used sophisticated computer encryption technology and file-sharing techniques," Matthew Friedrich, acting assistant attorney general, said in the statement. The seven defendants were James Freeman of Santa Rosa Beach, Florida; Gary Lakey of Anderson, Indiana; Marvin Lambert of Indianapolis, Indiana; Neville McGarity of Medina, Texas; Warren Mumpower of Spokane, Washington; Daniel Castleman of Lubbock, Texas; and Ronald White of Burlington, North Carolina, according to the Department of Justice.
Do you have any questions?
MY QUESTION: When will Daniel Castleman of Lubbock, Texas be sentenced?

QUES: Mechanical energy is a combination of the energy of motion or position. This type of energy describes objects that are moving or could move. A moving ball can have energy from motion. An arrow can also have the energy of motion. Both are types of mechanical energy. Can you think of some other examples? Where does the energy of motion come from? It comes from the energy created by position. This energy is stored energy. This means it is not moving yet, but it has the potential to move. How can you store energy? The arrow gains energy from the drawn bow. As the arrow is released, the bow releases its stored energy and puts the arrow into motion. Can you think of some other ways to store energy using position?
Do you have any questions?
MY QUESTION:
What does stored energy have the potential to do?