Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example Input: Context: A machine is any device that makes work easier by changing a force. When you use a machine, you apply force to the machine. This force is called the input force. The machine, in turn, applies force to an object. This force is called the output force. Recall that work equals force multiplied by distance: Work = Force Distance The force you apply to a machine is applied over a given distance, called the input distance. The force applied by the machine to the object is also applied over a distance, called the output distance. The output distance may or may not be the same as the input distance. Machines make work easier by increasing the amount of force that is applied, increasing the distance over which the force is applied, or changing the direction in which the force is applied. Contrary to popular belief, machines do not increase the amount of work that is done. They just change how the work is done. So if a machine increases the force applied, it must apply the force over a shorter distance. Similarly, if a machine increases the distance over which the force is applied, it must apply less force. Examples of machines that increase force are doorknobs and nutcrackers. Figure 16.8 explains how these machines work. In each case, the force applied by the user is less than the force applied by the machine, but the machine applies the force over a shorter distance. Examples of machines that increase the distance over which force is applied are paddles and hammers. Figure 16.9 explains how these machines work. In each case, the machine increases the distance over which the force is applied, but it reduces the strength of the applied force. Some machines change the direction of the force applied by the user. They may or may not also change the strength of the force or the distance over which it is applied. Two examples of machines that work in this way are claw hammers and the rope systems (pulleys) that raise or lower flags on flagpoles. Figure 16.10 explains how these machines work. In each case, the direction of the force applied by the user is reversed by the machine. How does this make it easier to do the job? An exoskeleton suit may seem like science fiction, turning ordinary humans into super heroes. But wearable robots are moving forward into reality. And for paraplegics, the ability to stand and walk that these machines provide is a super power. QUEST meets Austin Whitney and Tamara Mena, two "Exoskeleton Test Pilots" who are now putting this new technology through its paces. For more information on exoskeleton suits, see [Link] MEDIA Click image to the left or use the URL below. URL: You read above that machines do not increase the work done on an object. In other words, you cant get more work out of a machine than you put into it. In fact, machines always do less work on the object than the user does on the machine. Thats because all machines must use some of the work put into them to overcome friction. How much work? It depends on the efficiency of the machine. Efficiency is the percent of input work that becomes output work. It is a measure of how well a machine reduces friction. Consider the ramp in Figure 16.11. Its easier to push the heavy piece of furniture up the ramp to the truck than to lift it straight up off the ground. However, pushing the furniture over the surface of the ramp creates a lot of friction. Some of the force applied to moving the furniture must be used to overcome the friction. It would be more efficient to use a dolly on wheels to roll the furniture up the ramp. Thats because rolling friction is much less than sliding friction. As a result, the efficiency of the ramp would be greater with a dolly. Efficiency can be calculated with the equation: Efficiency = Output work 100% Input work Consider a machine that puts out 6000 joules of work. To produce that much work from the machine requires the user to put in 8000 joules of work. To find the efficiency of the machine, 
 Question: force applied by a machine
Example Output: output force

Example Input: Context: Feia Lacus is one of a number of hydrocarbon seas and lakes found on Saturn's largest moon, Titan. 
 Question: What celestial body can Feia Lacus be found on?
Example Output: titan

Example Input: Context: The film opens where the previous film ended, set a few years later, where Rafiki (Robert Guillaume) gathers the animals of the Pride Lands together for the presentation of Simba (Matthew Broderick) and Nalas (Moira Kelly) new daughter Kiara. Mufasa's spirit (James Earl Jones) watches over the ceremony. Later, Simba becomes very overprotective of an older Kiara (Michelle Horn), assigning Timon and Pumbaa (Nathan Lane and Ernie Sabella) to watch her. One day as Kiara was playing, she fell into a small pond as Timon and Pumbba got her back onto land. Kiara tells them only half of her is a princess. Pumbba asks, "Well, who's the other half?" While they wait for her to answer, they start having a snack. Then they started arguing about slimy and crunchy grubs. While they were arguing, Kiara sneaks into the "Outlands" where she meets a young cub named Kovu (Ryan O'Donohue). After escaping a river filled with nile crocodiles, the two become friendly, unaware they are being watched by Kovu's mother, Zira (Suzanne Pleshette). Simba arrives and confronts Zira, who reminds Simba that he exiled the Outsiders, and that if he wants to punish them, Kovu is Scar's hand-chosen successor. Unwilling to harm the cub, Simba orders them to leave. Later Simba scolds Kiara for endangering herself. In the Outlands, Zira's eldest son, Nuka (Andy Dick), complains to his younger sister Vitani (Lacey Chabert) about Kovu's status as "the Chosen One" the cub chosen by Scar to lead the pride after his death. ("I should've been the "Chosen One". I'm the strongest, I'm the smartest, I'm the oldest, etc.") At that moment, Zira returns and scolds both of her sons, but Kovu accidentally gives her the idea to use Kovu's new friendship with Kiara as a means of exacting her revenge on Simba for Scar's death. Now an adult, Kiara (Neve Campbell) heads out from home for her first solo hunt, however Simba again sends Timon and Pumbaa to follow and watch her progress after he promised to let Kiara hunt on her own. Furious to find out her father still insists on maintaining surveillance, Kiara goes further from home to hunt, though is still unsuccessful in her efforts. Meanwhile, Zira's plan to implant Kovu in Simba's pride has been set in motion; Nuka and Vitani (Jennifer Lien) set fire to the plains where Kiara is hunting, causing her to faint and giving Kovu (Jason Marsden) the chance to rescue her. Drawn by the smoke, Simba finds them together and reluctantly accepts Kovu's request to come to Pride Rock in return for saving Kiara's life, though he forces Kovu to sleep outside. That same night, Simba has a nightmare about his father's death, where Scar suddenly morphs into Kovu and Simba takes his father's place falling off the cliff. The next morning, he goes outside to a watering hole where Kovu contemplates attacking him, but Kiara interrupts and they go off together so Kovu can help her learn how to hunt. Kiara kept on failing. During the lesson, Kovu was setting an example for Kiara, thinking Timon was just an ordinary meerkat. They run into Timon and Pumbaa struggling with some birds, so the two lions help them chase the birds off. Together, they have fun playing, something Kovu notes he has never experienced before. That night, Kovu tells Kiara that he is not Scar's real son, but "was a part of him". Simba watches from above, seeking guidance from the "Great Kings" and Nala advises him to give Kovu a chance, because he is not his father. Kovu decides to leave after he almost confesses his real intentions to Kiara, but Rafiki stops him and invites the young lions to experience "Upendi" love. After a musical journey through the jungle, the two fall in love. In the morning, Simba invites Kovu for a walk and tells him the true story of 
 Question: Who leads Kovu and Kiara to the jungle?
Example Output:
rafiki