Question:
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? After reading the above, is "If the ball is in a position where it could move, it has the stored energy of position" the correct answer to the question "How can a ball that is not moving possess energy of position?"?

Answer:
yes

Question:
The inhabited history of the Las Vegas Valley stretches to 23,000 b.c. , when much of the area was covered by a prehistoric lake. During this period, the indigenous people lived in caves, hunting the mammals that gathered at the shoreline. The landscape of the valley changed dramatically over the next 200 centuries. The glaciers feeding the lake melted away and the lake evaporated. Fossils tell an obscure story of man's slow and sporadic development. Around 3000 b.c. , native Archaic Indians began to develop a lasting hunting and gathering culture. By this time, the valley was in much the same geographic state as it exists in today, with one exceptionthe presence of artesian springs that bubbled to the surface in several areas. These springs fed a network of streams draining through the Las Vegas Wash to the Colorado River. The areas surrounding the springs were desert oases: sprawling collections of grasses, trees, and wildlife. Many springs lay in areas that would eventually become the center of the modern Las Vegas metropolis. For about 4000 years, the Archaics thrived in a culture that included many signs of early civilization. Signs of even more advancement appeared halfway through the first millennium a.d. , when the Anasazi Indians inhabited the valley. Far more progressive than the Archaics, the Anasazi utilized such formal agricultural techniques as irrigation to assist their harvest. This permitted the Anasazi to achieve a benchmark of advanced societythe ability to live in permanent shelters year-round without need to follow wildlife. Mysteriously, the Anasazi vanished from the valley around a.d. After reading the above, is "The ice age started" the correct answer to the question "Why did the prehistoric lake disappear from the Las Vegas Valley?"?

Answer:
no

Question:
(CNN) -- Jo-Wilfried Tsonga ended Roger Federer's hopes of winning a record-equaling seventh Wimbledon title on Wednesday as the French 12th seed staged a stunning fightback to reach the semifinals. Federer appeared to be cruising into the last four after winning the first two sets, but Tsonga inflicted the Swiss world No. 3's first defeat from that vantage point in 179 grand slam matches. It was only the third time in the 29-year-old's glittering career that the 16-time grand slam champion had surrendered a two-set lead. Tsonga, ranked 19th in the world, triumphed 3-6 6-7 (3-7) 6-4 6-4 6-4 on Centre Court, serving out to love as he earned a clash with second seed Novak Djokovic. The Serbian, who beat Tsonga in the 2008 Australian Open final, ended the dream run of Australian 18-year-old Bernard Tomic. Tsonga defeated Federer for just the second time in six meetings, their first on grass. "It was amazing. I played unbelievable. It's never easy to come back against Roger. I'm so happy, it's crazy," the 26-year-old told reporters after reaching the semifinals at Wimbledon for the first time. "He's the biggest champion in the sport. He has achieved so much and is the best player in the world. To be two sets down and come back was unbelievable. I served really well. Against Djokovic I will have to come out and do the same again." Federer has now lost in the quarterfinals two years in a row, being beaten by eventual runner-up Tomas Berdych in 2010. "Jo played great. Really from start to finish I don't remember seeing a break point after I broke him in the first game," Federer said. After reading the above, is "Tsonga" the correct answer to the question "What two players beat Federer in the quarterfinals?"?

Answer:
yes

Question:
Elettra stuck the little slip of paper, on which the recipe was written, into her shabby pocket-book without looking at it. She could read and write fairly well, and had been used to helping her husband the under-steward with his accounts at Muro, but even if she had looked at the recipe she would have understood nothing of the doctor's hieroglyphics and abbreviated Latin words. The prescription was for a preparation of arsenic, which Matilde had formerly taken for some time. The chemist would not make any difficulty about preparing twenty doses of it for the Countess Macomer, though the whole quantity of arsenic contained in so many would probably be sufficient to kill one not accustomed to the medicine, if taken all at once. But though Matilde was so anxious to have the stuff before luncheon, she had a number of doses of it put away in a drawer, which she took out and counted, after Elettra had gone. She opened one of the little folded papers and looked at the fine white powder it contained, took a little on the end of her finger and tasted it. Then, from the same drawer, she took a package done up in coarser paper, and opened it likewise, looked at it, smelt it, and touched it with the tip of her tongue very cautiously indeed. It was white, too, but coarser than the medicine. She was very careful in tasting it, and she immediately rinsed her mouth with water, before she tied up the package again, shut the drawer, and put the key into her pocket. After reading the above, is "Not clear" the correct answer to the question "Did Elettra take arsenic in the past?"?

Answer:
yes