Unit II machines and work

to apply – застосовувати

to accomplish – здійснювати, виконувати

block and tackle – система двох або декількох блоків, з’єднаних канатом

exert – здійснювати, викликати

prime mover – машина-двигун, головний двигун

foot-pound – футо-фунт

translation – переміщення, зсув, прямолінійне пересування

go back and forth – рухатися назад і вперед

path – шлях

torque – момент обертання; зусилля, що скручує

torsion – крутіння, скручування

twist - крутіння, скручування

stress – тиск, натискання

resistance – опір

imply – означати

input – підведена потужність

output – ефективна потужність

effort – зусилля

exert force – докладати зусилля

time – хронометрувати, вимірювати

overcome – подолати

output of work – продуктивність роботи

utilize – використовувати

bear – переносити

braking devices – гальмівний пристрій

rate – швидкість, темп

Special Terms:

Machine: A device that applies force to accomplish an objective.

Force: An effort that results in change in motion or stress.

Work: The effect of a force multiplied by the distance through which it is exerted.

Block and Tackle: A variation of one of the basic machines; it uses the principle of a lever.

Prime Mover: A machine which converts energy from a natural source like water, wind, steam, or petroleum into mechanical energy or electricity. Most electric motors are not prime movers.

Foot-pound: Work is usually measured in terms of foot-pounds in the English-speaking countries. One foot-pound is a force of one pound through a distance of one foot in the direction of the force.

Linear Motion: Motion in a straight line; technically it is known as translation.

Reciprocating Motion: A linear motion that goes back and forth in the same path.

Rotary Motion: Motion in a circular path.

Torque: A force which produces torsion, a twisting stress or rotary motion.

Efficiency: A machine's ratio between work output and energy in­put.

Friction: The resistance to relative motion produced by two moving bodies in contact with each other.

Power: The rate or speed at which work is performed.

Newton: The unit of force required to accelerate one kilogram one meter per second.

Joule: An international metric measure of energy; one joule is ap­proximately.

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

Kilowatt: A thousand watts; approximately 3/4 horsepower in the English system.

Vocabulary Practice

1. What is the technical definition of a machine?

2. In speaking of machines, what does force mean?

3. What does work mean?

4. What is a block and tackle?

5. What is a prime mover? What kinds of machines usually are not prime movers?

6. What are foot-pounds? How much is one foot-pound?

7. What is linear motion? What is it called technically?

8. What is reciprocating motion?

9. What is rotary motion?

10. What does torque mean?

11. Speaking of machines, what does efficiency indicate?

12. What produces friction?

13. What does power mean?

14. What is a Newton?

15. What is a joule?

16. What is a watt? How many watts are there in a kilowatt?