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: "How would gravity affect a book resting on a table/"

OPTIONS:
- no
- yes

Answer: "Gravity would push down on the book"

Response: yes

Have you ever looked closely at a globe? That continents look like a giant jig-saw puzzle. North America looks like it could fit next to Europe. The edge of South America matches Africa. Scientists noticed these same features. It caused them to start asking questions. They wanted to know if these continents were was connected? If so, how can something so large move so far? What could possibly have enough force to move such a giant slab of rock? Is there other evidence that can provide clues to the past positions of continents? How can answering these questions help us? A scientist named Alfred Wegener had these same questions. Wegener look at rocks on both sides of the Atlantic Ocean. He noticed they were the same type and age. He thought that the rocks must have formed side by side. He proposed that the rocks then drifted apart. One part went with North America. The other part stayed with Europe.

Question: "Which four continents from the paragraph look like they are connected like a jig saw puzzle?"

OPTIONS:
- no
- yes

Answer: "Puzzle"

Response: no

The modern Republic of Turkey dates only from 1923, but the history of the land within its borders stretches back to the dawn of humanity. Widespread finds of Stone Age implements in cave excavations show that Anatolia was already inhabited during the Middle of the Palaeolithic period (about 200,000 to 40,000 years ago). By Neolithic times, organized communities had arisen, such as the one at Catalhoyuk, near Konya, Turkey's most important prehistoric site. This town, which flourished between 6500 and 5500 b.c. , had flat-roofed houses of mud and timber decorated with wall-paintings, some of which show patterns that still appear on Anatolian kilims. The advent of the Bronze Age (about 3200 b.c. ), and the spread of city-states ruled by kings, is marked by the appearance of royal tombs containing bronze objects in such places as Troy in the west, and Alacahoyuk near Ankara. Around this time the Sumerian civilization living in Mesopotamia (the region between the Tigris and Euphrates rivers in present-day Iraq) founded and developed the cuneiform script, the world's oldest form of writing on record. The technique was introduced by Assyrian traders 1,000 years later into Anatolia, where it was quickly adopted by the indigenous Hatti people, who, at this point, had already reached an advanced state of civilization. The Hittites: The capital of the Hatti was Kanesh (modern Kultepe, near Kayseri). Cuneiform tablets found here record the arrival in Anatolia of warlike invaders around the second millennium b.c. Their origins remain a mystery (their written language was finally deciphered in 1915), but they came from the direction of the Caucasus mountains, spreading destruction and disorder throughout Anatolia. It was two hundred years before they were firmly entrenched in their newly conquered empire. The newcomers were the Hittites, and their domination of Anatolia can be divided into three distinct periods: the Old Kingdom (c. 16001450 b.c. ), then the New or Empire Period (c. 14501200 b.c. ), and the Late Hittite Period (c.

Question: "What is marked by the appearance of royal tombs containing bronze objects?"

OPTIONS:
- no
- yes

Answer: "The advent of the Bronze Age"

Response: yes

(CNN) -- A Christian evangelical group said Thursday that a Bible school -- backed by American evangelist Franklin Graham -- was destroyed in the latest bombing raid to hit South Kordofan, an oil-rich Sudanese province that borders the newly created independent country of South Sudan. At least eight bombs were dropped in the area Wednesday during the school's first day of classes, according to a statement by Samaritan's Purse, Graham's Christian humanitarian group, which supports the school. Two bombs landed inside the compound -- located in the region's Nuba Mountains -- destroying two Heiban Bible College buildings and igniting grass fires across the area, the group said in a statement No injuries were reported. "It was a miracle that no one was injured," the statement added. Graham, who has called on the international community to take out Sudan's air assets and establish a no-fly zone in the region, said in a statement Thursday that he blamed Sudan's air force for the strike. At least four churches have been destroyed since August, the group said. "We are deeply concerned for the welfare and lives of the people of South Kordofan and we condemn the bombing of churches and Christian facilities," added Graham, son of the famed Rev. Billy Graham. More than 78,000 people have fled South Kordofan and Blue Nile states since August of last year after an armed rebellion took root, the United Nations reported. The Sudanese government is thought to have responded to the rebellion by conducting sustained air raids with the use of Russian-made Antonov bombers, which have raised concerns over civilian casualties. Decades of civil war between the north and south, costing as many as 2 million lives, formally ended with a U.S.-brokered peace treaty in 2005.

Question: "What religion did these churches worship?"

OPTIONS:
- no
- yes

Answer: "Christian"

Response:
yes