A、One-sixth pound. B、One-fourth pound. C、One-third pound. D、Half a pound. B

We are so used to our life on the surface of the earth that it is not easy for our minds to break free of all the ideas that we take for granted. For example, we can feel things are heavy, so we think of "weight" as being a fixed quality in an object. But actually it is not fixed at all. If you could take a one-pound packet of butter 4,000 miles out from the earth, it would weigh only a quarter of a pound. The reason for such a change of weight is this: all objects have a natural attraction for all other objects; this is called gravitational attraction. But this power of attraction between two objects gets weaker as they get farther apart. So the weight of an object on the surface of the earth is not the same as its weight 4,000 miles out in space.
    What about the weight of one pound of butter on the surface of the moon? There will be attraction between the butter and the moon: but the butter will weigh only about one-sixth as much as it does on the earth. This is because the moon is so much smaller than the earth. The amount of the gravitational pull that a body produces depends on the amount of material in it. A packet of butter has a gravitational pull of its own, but it is very small in relation to the pull of something as large as the moon or the earth.
Question No. 23 According the speaker, what quality of an object is taken for granted by people?
Question No. 24 How much will a pound of butter weigh if it is brought 4,000 miles into space?
Question No. 25 What is the gravitational attraction?
Question No. 26 Why does an object weigh much less on the moon than it does on the earth?