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Flashcards in Shock Waves Deck (75)
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1

What is Mach number ?

It is the ratio of the speed of object to the speed of sound in the same medium

2

What is an acoustic wave ?

It is simply a sound wave

3

What is the velocity of a sound wave at STP in air ?

Around 333 m/s

4

What are the frequencies acoustic waves lie in ?

20 to 20,000 Hz

5

What are ultrasonic waves ?

Pressure waves that have frequencies greater than 20,000 Hz

6

What is the speed of an ultrasonic wave ?

Same speed as sound

7

What is a subsonic wave ?

A mechanical waves moving in a fluid with velocity less than that of sound

8

What is the Mach number so subsonic waves ?

Less than 1

9

What are some examples of subsonic motion ?

Vehicles such as motor cars and trains, birds

10

Where does the sound emitted by a body moving with subsonic motion go ?

It goes ahead of the body and moves away

11

What is a supersonic wave ?

It is a mechanical wave which travels with a speed greater than that of sound

12

Where does the sound emitted by a body travelling with supersonic speed go ?

The body moves ahead by piercing it's own sound curtain

13

What kind of wave is formed by supersonic motion ?

A series of expanding sound waves, with their centers continuously displaced along trajectory

14

What is the amplitude of a supersonic wave ?

It is high, and affects the medium

15

What is Mach cone, formed at supersonic speed ?

A number of tangents drawn to the expanding sound waves for a Mach cone

16

What are hypersonic waves ?

Mach number greater than 5 Special case of supersonic waves

17

What are transonic waves ?

Mach number in between 0.8 and 1.2 Domain in which change of phase from subsonic to supersonic occurs

18

What is a shock wave ?

It is a surface that manifests as a sudden discontinuity in a fluid medium, in which it is propagating with supersonic speed

19

What does a shock wave cause ?

Sudden increase in pressure, temperature and density of gas through which it propagates

20

What is a closed system ?

A system that does not exchange matter with outside and not acted upon by external forces

21

What is the law of conservation of matter ?

The total mass of any isolated system remains unchanged, regardless of any physical or chemical change within it

22

What is the law of conservation of momentum ?

In a closed system, total momentum remains constant

23

What is the law of conservation of energy ?

The total energy of a closed system remains constant and is independent of any changes within the system

24

What is extra-corporal lithitripsy ?

It is a shock wave therapy for treating kidney stones

25

What happens in it ?

The kidney stones are shattered into fragments

26

What happens to the shattered kidney stones ?

Smoothly passed out through urinary tracts

27

How can shock waves assist in drug delivery ?

It can replace needles

28

How are drugs delivered using shock waves ?

The drug is kept in a cartridge and pressed to the skin

29

How does the shock wave enter ?

Directly through the porosity of the skin

30

What is the normal penetration ?

About 100 microns