If a bag of sugar weighs 6 kilograms on earth, what will it weigh on the moon? It will weigh one kilogram on the moon, 1/6 of its weight on the earth.

Here on the earth we usually talks as if weight and mass were the same thing. We use weight as a way of measuring mass. On the earth this is very convenient. A mass of sugar that weighs 6 kilograms in California will weigh about 6 kilograms in Hawaii or Canada or Germany. Because the force of gravitation in each place is practically the same.

As long as we stay on earth, using weight to measure mass works pretty well. Now, however, men have left the earth. Suddenly we realize that weight and mass are not the same thing! Away from the earth the force of gravitation changes. As the pull gravitation changes, weight changes, but the mass of an object stays the same anywhere in the universe—whether it is on earth, on the moon, or on Mars.

Have you ever wondered why the pull of gravitation on the moon is only 1/6 of the pull on the earth? Here is a reason. When the mass is less, gravitation is less. The moon has less mass than the earth. Since the moon has much less mass than the earth, it has much less gravitational force than the earth.

1.Which of the following is NOT true?

A. Few people on the earth would pay much attention to the difference between weight and mass.

B.The weight of an object hardly changes wherever on the earth it is weighed.

C.The weight of an object becomes less on the moon because the moon is far away from the earth.

D.Mass is a concept(概念)more important than weight in the study of the universe.

2.The amount of mass depends on 　　  .

A. the weight of an object?　　　　　　　　　　　　　　 B.the place where it is measured

C.the size of an object?　　　　　　　　　　　　　　　　  D.the amount of matter it is made of

3.An astronaut, who weighed 30 pounds on the moon, is back on earth and now weighs 165 pounds. How much weight did he lose during his flight back to the earth?

A.115 pounds.　　　　　　   B.2.5 pounds.?　　　　    C.30 pounds.　　　　　　    D.15 pounds.

4.We can infer from the passage that the word “Mars” means 　　  .

A. a faraway place on the earth

B.a place deep down in the ocean

C.a kind of flying equipment like a spaceship

D.a planet which is farther away from the earth than the moon is

　 —Flight 302 to Paris ______ until 7:30 tomorrow morning.

?—No wonder I hear so many complaints from the passengers.

　 A. put off　 B. has been put off　 C. will put off　 　 D. had been put off

Remember what weight is? Weight is the gravitational pull on an object. If, somehow, the pull of gravitation changes, then the weight of the object changes. The mass of the object, the amount(数量)of matter it is made of, does not change.

If a bag of sugar weighs 6 kilograms on earth, what will it weigh on the moon? It will weigh one kilogram on the moon, 1/6 of its weight on the earth.

Here on the earth we usually talks as if weight and mass were the same thing. We use weight as a way of measuring mass. On the earth this is very convenient. A mass of sugar that weighs 6 kilograms in California will weigh about 6 kilograms in Hawaii or Canada or Germany. Because the force of gravitation in each place is practically the same.

As long as we stay on earth, using weight to measure mass works pretty well. Now, however, men have left the earth. Suddenly we realize that weight and mass are not the same thing! Away from the earth the force of gravitation changes. As the pull gravitation changes, weight changes, but the mass of an object stays the same anywhere in the universe—whether it is on earth, on the moon, or on Mars.

Have you ever wondered why the pull of gravitation on the moon is only 1/6 of the pull on the earth? Here is a reason. When the mass is less, gravitation is less. The moon has less mass than the earth. Since the moon has much less mass than the earth, it has much less gravitational force than the earth.

1.Which of the following is NOT true?

A. Few people on the earth would pay much attention to the difference between weight and mass.

B.The weight of an object hardly changes wherever on the earth it is weighed.

C.The weight of an object becomes less on the moon because the moon is far away from the earth.

D.Mass is a concept(概念)more important than weight in the study of the universe.

2.The amount of mass depends on 　　  .

A. the weight of an object?　　　　　　　　　　　　　　 B.the place where it is measured

C.the size of an object?　　　　　　　　　　　　　　　　  D.the amount of matter it is made of

3.An astronaut, who weighed 30 pounds on the moon, is back on earth and now weighs 165 pounds. How much weight did he lose during his flight back to the earth?

A.115 pounds.　　　　　　   B.2.5 pounds.?　　　　    C.30 pounds.　　　　　　    D.15 pounds.

4.We can infer from the passage that the word “Mars” means 　　  .

A. a faraway place on the earth

B.a place deep down in the ocean

C.a kind of flying equipment like a spaceship

D.a planet which is farther away from the earth than the moon is