Present simple past simple tense

1. Here are the past tense forms of some verbs. Write in the base forms:

………………………set …………………………rode

………………………reached …………………………was

………………………managed …………………………did

………………………weighed

Three of them end in – ed. They are the past tense forms of regular verbs. The others are irregular.

2. Read the sentences below:

a./ In 1958, Eli Beeding, Jr rode a rocket sledge when it was shot along a track from a standstill to a speed of 72.5 mi / h ( = 117 km / h ) in a fantastic time of 0.04 s ( less than the blink of an eye ).
b./ In 1977 Kitty O’Neil set records for “ terminal speed” and “ elapsed time” for a dragster on a 440 – yd run. From a standstill, she reached 392.54 mi/h ( about 632.1 km/h ) in a sizzling time of 3.72 s.
c./ On April 4, 1974, John Massic of Belgium managed to move two passenger cars. He did so by clamping his teeth down on a bit that was attached to the cars with a rope. The car weighed about 80 tons. Did Massic have superhuman force to accelerate the cars?
3. Work in pairs

Ask and answer questions about the paragraphs.

− A rocket sledge.

− Why is the past simple tense used in the paragraph?

− How do we form the questions?

− How do we form the negatives?

1. The present simple or the past simple . Put the verbs in brackets in the correct

forms:

a. Thrust SSC (supersonic) car ……………(be) the invention of Briton Richard Noble. In 1983 he ……………(set) the world speed record of 1,019.44 km / h.

century, there ……………(be) much arguing and debating of this controversial idea.

c. The ancients ………………(believe) that light ………………(travel) from our eyes to the objects we ………………(look at), rather than from the objects to our eyes.

d. On October 17, 1989, a devastating earthquake ………………(strike) central California.

f. Motion in space …………………( affect ) motion in time.

g. When we ……………(sit) on a fast – moving train , we ……………(have) no speed at all relative to the train.
2. There are three pronunciations of the past tense ending –ed:

/ t / / d / / id /

Put the regular past tense forms in exersice 1 into the correct columns. Give more examples of the three pronunciations.

Work in pairs

Ask and answer question:

− What did you do last night?

last month?

last weekend?

on your last birthday?

− I watched TV / went to the cinema.

• Reading and speaking

1. Use your dictionary to check the meanings of these words below:

force (n) reach (v)

lean (v) observation (n)

resistance (n) get into trouble (v)

a. Force laws tell us how to calculate the ……………that will act on a body in a particular environment.

b. Do not …………………out of the window, you may fall.

c. Captain Robert Scott ………………the South Pole on January 17, 1912.

d. Astronomers often use telescopes to take an ……..… of stars in the sky.

e. Do not speed up. We may …………… with the police.

f. You don’t notice air ………………when walking, but you’ll notice it when skiing downhill.
3. Read the text about Galileo Galile:
GALILEO GALILEI

(1564 – 1642)

The idea that a force causes motion goes back to the fourth century B.C, when the Greeks were developing ideas of science. The foremost Greek scientist was Aristotle. He studied motion and divided it into two kinds: natural motion and violent motion. Aristotle said that heavy things fall faster than light things; but he was wrong. Most of the later scientists believed Aristotle. This remained true until the time of Galileo, the Italian scientist . Galileo did not believe him.
Fig.1 Galileo’s famous demonstration
He went to school at Vallombrosa, near Florence, Italy. He tried to learn science there, but he did not like it. He went to the University of Pisa to continue his studies. There is a famous tower at Pisa. It does not stand straight up, but leans a little more each year. Galileo climbed to the top of the leaning Tower, and there he dropped two weights. One of them was heavier than the other, but they reached the ground at the same moment. Many scientists witnessed his experiment and they were very surprised. This did not agree with Aristotle’s rule. Galileo showed that falling objects have equal accelerations, regardless of their masses. But Galileo could not say why the accelerations were equal. Galileo made many other experiments, and he also made some telescopes. When he pointed a telescope at the moon, he saw some hills there. He also saw some of the millions of stars in the universe – more than anyone had ever seen. He thanked God, who let him see these wonderful things. In 1637 Galileo’s eyes failed, and then he could not see anything through his telescope. Five years later he died. The world then lost a great man, but in the same year (1642) another great scientist, Sir Isaac Newton, was born in England. He truly changed our way of seeing the world.

( From Elementary Scientific English Practice )

Comprehension check

1. Are the statements true or false. Correct the false ones:

a. Galileo’s experiment from the Leaning Tower of Pisa demolished the Aristotelian

ideas of motion.

b. Galileo’s experiment explained why falling objects have equal accelerations,

regardless of their masses.

c. Galileo did not see anything when he pointed his telescope at the moon.

d. He died at the age of 78.

a. Was Aristotle right when he said that heavy things fall faster than light things?

b. Why is the tower of Pisa famous?

c. Where did Galileo make his experiment?

d. What was the result of his experiment?

e. What did he study with telescopes ? Was he successful in his studies?

f. What happened in 1637?

g. When did he die?

h. Who was born in the same year when Galileo died?
3. Further question for discussion

Newton’s second law explained the result of Galileo’s experiment at the Leaning

Tower of Pisa. Do you know why? State Newton’s second law in words.
• Listening and reading

1. You will hear and discuss a concept summary that gives meanings of some important terms. These terms are related to part “ Mechanics”
2. Read the following definitions. There is a mistake in each definition. Listen and correct the mistakes:
a. Free fall

An object in free fall is falling under the influence of mass alone, where air resistance does not affect its motion.

The mass of an object depends on the location of the object.

Friction is a force that does not always react in a direction to oppose motion.

Acceleration is the rate at which speed is changing with respect to time.

Impulse is force multiplied by the distance in which it acts.

Some quantities require magnitude for a complete description; these are vector quantities.

The force per unit of length is called pressure.

# Present Simple

_ The Present Simple expresses a fact which is true for a long time.

# Past Simple

_ The Past Simple expresses a finished action in the past.
• Translate:

1. We often need to change the units in which a physical quantity is expressed. We do so by a method called chain – link conversion.

2. Motion at constant velocity is motion in a straight line.
3. Aristotle did not recognize the idea of inertia because he failed to imagine what motion would be like without friction.

4. Newton was the first to realize that the acceleration we produce when we move something depends not only on how hard we push or pull but on the mass as well.

How do seat belts in cars save lives?

I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

II. The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector.

III. For every action there is an equal and opposite reaction