3. Answer the following questions:

   1. What types of deformation do you know?

   2. What is elastic deformation?

   3. What do you know about metal fatigue?

   4. When do the cracks appear?

   5. What are the two ways to determine when a part is in danger of metal fatigue?

   6. What is plastic deformation?

   7. What do you know about fracture?

3. Complete the sentences with the appropriate words from the text:

   1. Metal _______ has been a major cause of aircraft failure, especially before the process was well understood.

   2. Ceramics, crystals, and hard thermosetting _______ undergo almost no elastic deformation.

   3. Soft thermoplastics and metals have moderate _______ deformation ranges.

   4. A phenomenon only discovered in modern times is metal fatigue, which occurs primarily in _______ metals.

   5. Soft thermoplastics have a rather large plastic _______ range as do ductile metals such as copper, silver, and gold.

   6. Hard thermosetting plastics, rubber, crystals, and ceramics have _______ plastic deformation ranges.

   7. All materials will eventually fracture, if _______ forces are applied.

5. Make up word combinations from the following words, translate them into Ukrainian.

   1. metal a) deformation

   2. ductile b) fatigue

   3. microscopic c) shape

   4. thermosetting d) cracks

   5. molecular e) metals

   6. elastic f) level

   7. original g) plastics

5. Finish the following sentences:

   1. Depending on the type of material, size …….

   2. Soft thermoplastics and metals have moderate …….

   3. After many deformations, cracks will begin …….

   4. Avoiding shapes with sharp corners limits metal fatigue …….

   5. Selection of materials which are not likely to suffer …….

   6. There are two ways to determine when a part is in danger …….

   7. However, an object in the plastic deformation range …….

7. Match the words with their definitions:

object, material, crack, metal, fatigue, fracture, deformation.

1. The action of deforming or process of being deformed.

2. Any solid shiny mineral substance which can be shaped by pressure and used for passing an electric current.

3. Anything from which something is or can be made; natural or man-made substance.

4. The cracking or breaking of something.

5. A line of division caused by splitting; very thin mark or opening caused by breaking, but not into separate parts.

6. The tendency of a metal to break as the result of repeated bending.

7. A thing that can be seen or felt.

8. Match English words with their Ukrainian equivalents:

1) fatigue a) податливий(матеріал)

2) crack b) розрив

3) fracture c) реверсивний

4) iteration d уразливий(матеріал))

5) reversible e) тріщина

6) ductile f) утома(матеріалу)

7) vulnerable g) повторення

9. Express the main idea of the text in the shortest possible way. Lesson 3

1. Find in the text English equivalents for the following Ukrainian words and word combinations:

напруга, ламкий, опір матеріалів, поведінка, границя, навантаження, втрата тривкості, поломка, можливо, повторний, траплятися, значення, ущільнення, зразок, піддавати впливу, відносини, опір, деформація, проміжний, нееластичність, важливий, площа, межа еластичності, роз тягальна напруга, дотична напруга, випадок.