Английский язык. Ч. 1. Ильичева Н.А - 6 стр.

                                            6
                                    Test2 (Unit2)
                                  Force and Motion

       A. Reading.
       You are going to read an article about motion and force. Five sentences
have been removed from it. Choose from the sentences (A-E) the one which fits
each gap (1-5).
       Intuitively, we experience force as any kind of a push or a pull on an object. 1.
   . When a motor lifts an elevator or a hammer hits a nail, or the wind blows the
leaves of a tree, a force is being exerted. We say that an object falls because of the
force if gravity.2. . For example, you may push very hard on a heavy desk and it
may not move. The more mass a body has, the harder it is to change its state of mo-
tion. 3. . It is much harder to speed it up or slow down. Observations suggest that a
force applied to any object is always applied by another object. 4. . In each of these
examples, a force is exerted on the body, and that force is exerted by another body.
But things are not one-sided. True, the hammer exerts a force on the nail. 5. .

        A. A horse pulls a wagon, a hammer pushes on a nail, a magnet attracts a paper
clip.
    B. Forces do not always give rise to motion.
    C. But the nail evidently exerts a force back on the hammer as well, for the
hammer’s speed is rapidly reduced to zero upon contract.
    D. When you push a grocery cart or a stalled car, you are exerting a force on it.
    E. A truck has more inertia than a baseball.

        B. Choose the correct item to fill in the gaps.
        1. To Aristotle, the natural state of an object was one of…………(leisure, rest,
relaxation)
        2. In free space where there is no…………and negligible gravitation, an object
initially in motion maintains a constant velocity. (rubbing, scraping, friction).
        3. The more…………a body has, the harder it is to change its state of motion. (
mass, size, weight).
        4. To every action there is an equal and opposite…………(reply, attitude, reac-
tion).
        5. Inertia is the property that…………changes in motion (resists, rejects,
stops).
        6. Mass refers to the amount of matter an object …………(accommodates,
holds, contains).
        7. Because of the ever-present forces of friction and gravity on Earth, it is dif-
ficult to observe an object in a………….state of constant velocity. (typical, natural,
common)
        8. Weight is related to the force of ………… (gravity, pressure, compression)
        9. An …………, unbalanced force is required to produce a change in velocity.
(outward, exterior, external)