4. Choose the right statement:

1). Tensile stress … stress when the external and internal forces are perpendicular (normal) to the cross-sectional area under con­sideration.

a)is not normal;

b) normal;

c) usual.

2) … data are widely used in designing machinery, buildings, bridges, dams, and other structures.

a) Price-of-materials;

b) Electrical-saving;

c) Strength-of-materials.

3). The three … of stress are tensile stress, compressive stress, and shearing stress.

a) main kinds;

b) works;

c)risk groups.

5. Fill in the gaps.

Stress in a body (1) as resistance to external forces. It (2) in terms of the force exerted per unit of area. Generally, (3) is given in pounds and the resisting area in square inches. Consequently, stress usually is expressed (4) per square inch (psi). Sometimes it is expressed in kilo-pounds per square inch, which is commonly ab­breviated as (5).

1). a) finds; b) will be able to defined; c) can be defined.

2). a) is measured; b) was calculated; c) will be signed.

3). a) the horse power; b) the force; c) the area.

4). a) in pounds; b) in kilos; c) in grams.

5) a) tips ; b) kips; c) chips.

6. Complete the sentences.

engi­neering, behavior, designing, withstand, resisted, joints, strains, designers, exerted, shearing,

Strenth of materials is a branch of 1)____ . It deals with the 2)____ of materials in response to applied forces. Strength-of-materials data are widely used in 3)____ machinery, buildings, and other structures. The parts of a bridge, for example, must be strong enough to 4)____ the various kinds of forces placed on the bridge by traffic, wind, and other agents. These applied forces are 5)____ by internal forces, called stresses in the bolted, riveted, or welded 6)____ between parts. Changes of shape, are known as 7)____. Hence bridge 8)____ rely on strength-of-materials data to specify suitable materials for the various parts of the bridge. Stress is measured in terms of the force 9)____ per unit of area. The three main kinds of stress are tensile stress, compressive stress, and 10)____ stress.

a) withstand, b) designing, c) resisted, d) behavior, e) joints, f) strains, g) engi­neering, h) exerted, i) shearing, j) designer.

7. Group the synonyms.

1)cause, 2)flexible, 3)quality, 4)outside, 5)external, 6)form, 7)area, 8)reason, 9) property, 10)internal, 11)motive, 12)shape, 13)elastic, 14)square, 15)space, 16)inside17)territory,18)deform, 19)constant, 20)change, 21)permanent, 22)strain. 23) tension, 24) characteristics,

UNIT 4

1. Learn the notions and their definitions.

Kinematics A branch of the science of mechanics that deals with aspects of motion apart from considerations of mass and force.

Vectors directional quantities.

Scalar denotes the physical quantities that have no idea of direction associated with them.

The position vector the directed segment on the "x-axis".

Coordinate numbers attached to or coordinated with a geometrical object and characterizing this object completely.

Horse-power a unit for measuring the amount of work performed per second.

Joule An international metric measure of energy; one joule is ap­proximately three-quarters of a foot-pound.

Watt An international metric measure of power equal to one joule per second; 746 watts are equal to one horsepower.

Kilowatt: A thousand watts.

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