Problem: Rough surfaces create more friction than smooth surfaces. Thats why cars have tires. Its also why we use rubber mats in areas that might get wet. In your bathtub, you may even use No-Slip tape. No-slip is another way of saying the items has a lot of friction. In Figure 1.9, the blades of the skates are very smooth. Thats why you cant slide across ice with shoes. The soles of your shoes are much rougher than skates. The rougher surface of shoes causes more friction and slows you down. Heavier objects also have more friction. A heavy object presses down with more force. The surfaces are held together more tightly. This makes the surfaces harder to slide past each other. Did you ever try to push something heavy across the floor? Heavy objects are much harder to push than light objects.

Question: "Why can't you slide across an ice in your shoes the way you would in skates?"

Answer: "The blades of the skates are very smooth"

OPTIONS:
- no
- yes
Answer: yes

Problem: Earths magnetic field helps protect Earth and its organisms. It protects us from harmful particles given off by the sun. Most of the particles are attracted to the north and south magnetic poles. This is where Earths magnetic field is strongest. This is also where relatively few organisms live. Another benefit of Earths magnetic field is its use for navigation. People use compasses to detect Earths magnetic north pole. Knowing this helps them tell direction. Many animals have natural 'compasses' that work just as well. Birds like the garden warbler in Figure 1.36 use Earths magnetic field. They use it to guide their annual migrations. Recent research suggests that warblers and other migrating birds have structures in their eyes. These structures let them see Earths magnetic field as a visual pattern.

Question: "According to this passage, what protects the organisms of Earth from harmful particles given off by the sun?"

Answer: "Earths magnetic field"

OPTIONS:
- no
- yes
Answer: yes

Problem: But I think it is certain that most of the early Christians understood these words of our Lord's ascension and coming again in glory. They believed that He was coming again in a very little while during their own life-time, in a few months or years, to make an end of the world and to judge the quick and the dead. And as they waited for His coming, one generation after another, and yet He did not come, a sadness fell upon them. Christ seemed to have left the world. The little while that He had promised to be away seemed to have become a very long while. Hundreds of years passed, and yet Christ did not come in glory. And, as I said, a sadness fell on all the Church. Surely, they said, this is the time of which Christ said we were to weep and lament till we saw Him again--this is the time of which He said that the bridegroom should be taken from us, and we should fast in those days. And they did fast, and weep, and lament; and their religion became a very sad and melancholy one--most sad in those who were most holy, and loved their Lord best, and longed most for His coming in glory.

Question: "Did early Christians believe Christ was coming back to the world?"

Answer: "For sure"

OPTIONS:
- no
- yes
Answer:
yes