Noise and Vibration

Question 1

Define sound

Answer 1

mechanical radiant energy that is transmitted by pressure waves in an elastic material/medium (such as air) and is the objective cause of hearing

Question 2

Define noise

Answer 2

sound that is loud, unpleasant or unwanted. However, sound does not have to be loud

Question 3

What are the three measurable characteristics of noise?

Answer 3

F.I.D
Frequency
Intensity
Duration

Question 4

Identify the effects of noise on the body

Answer 4

annoyance, fatigue, speech interference, and hearing loss

Question 5

How does noise cause fatigue?

Answer 5

Fatigue can be caused by a number of physiological responses that have been attributed to noise. Reported responses include effects on blood flow to the skin, respiration, skeletal muscle tension, and constipation

Question 6

How does an annoying noise affect crewmwmbers while they are performing their duties

Answer 6

Annoying noise can affect pilots while they are performing their duties because it interferes with concentration

Question 7

TRUE OR FALSE: The denser the substance, the faster and longer the sound will travel

Answer 7

TRUE! The density of the substance determines the speed at which the sound and pressure waves will travel. The denser the substance, the faster and longer the sound will travel

Question 8

The Surgeon General has establish ____ as the maximum permissible sound level of continuous, unprotected exposure to steady-state noise for _____ hrs

Answer 8

85 decibels, 8 hrs

Question 9

For every _____ decibel noise increases, exposure time is cut in _____

Answer 9

5, half For every five decibel noise increases, exposure time is cut in half

Question 10

Types of hearing loss

Answer 10

• Conductive Hearing Loss (impediment in the external or middle ear)
• Sensorineural Hearing Loss (Cochlea is damaged)

Question 11

Of the two types of hearing loss, which is considered responsive to medical treatment

Answer 11

Conductive Hearing Loss

Question 12

Of the two types of hearing loss, which is considered permanent and not responsive to medical treatment

Answer 12

Sensorineural Hearing Loss

Question 13

Since loud noise exposures usually can be predicted, what is the best way to conserve hearing in such hazardous noise environments.

Answer 13

Wear hearing protection in high noise environments to protect hearing.

Question 14

The HGU-56 and IHADSS helmets protect against aircraft noise on all but two army aircrafts, what are they?

Answer 14

UH60 and CH47

Question 15

What is vibration

Answer 15

a series of oscillations resulting in the displacement and acceleration of the object (usually the object begins at rest)

Question 16

the maximum displacement of an object from its position at rest is

Answer 16

Amplitude

Question 17

the mechanical amplification of vibration by the body occurring at specific frequencies is called

Answer 17

Natural body resonance

Question 18

A loss of mechanical energy in a vibrating system. causeing the vibration to slow down is know as

Answer 18

Damping

Question 19

When does the highest level of vibration occur during flight

Answer 19

Hover to flight and flight to hover

Question 20

What are the short-term effects of vibration on the body

Answer 20

Fatigue, respiratory effects, circulatory effects, motion sickness, disorientation, and pain

Question 21

How does vibration cause fatigue?

Answer 21

Vibration causes the muscle to contract (exercise) For example, vibration placed on both calves of a standing subject resulted in the subject experiencing the sensation of leaning forward (constant exercise)

Question 22

The result of vibrating frequencies in the diaphragm will cause

Answer 22

Respiratory effects The result of these “artificial respiration” could lead to hyperventilation if the diaphragm is vibrated at 4-8 hertz

Question 23

What are the long-term effects of vibration on the body

Answer 23

Raynaud’s disease, Backache/back pain, and kidney/lung damage

Question 24

TRUE OR FALSE: Backache/back pain in aircrew member may result at an earlier age than normal

Answer 24

TRUE! Backache/back pain in aircrew member may result at an earlier age than normal. The lumbar spineis subjected to higher pressures during aircraft operation because the weight of the torso on that part of the spine while sitting.

Question 25

what is Raynaud’s Disease?

Answer 25

Raynaud’s Disease (White finger) occurs to the hands after prolonged exposure to vibration from power tools, jackhammers, or other such equipment that vibrates at high frequencies. Trauma occurs in the arterioles and nerve endings in the extremities and limits the blood flow to that portion of the extremity

Question 26

Identify the effects of vibration on vision during flight

Answer 26

Vision could be affected due to vibration in the aircraft; visual instruments may be difficult to read. Helmet mount or night vision devices may vibrate at 4-12 Hz

Question 27

At what level is speech distorted from the affects of vibration

Answer 27

Speech can be distorted during oscillations of 4-12 Hz. Above 12 Hz, speech becomes increasingly difficult to interpret

Question 28

__________ is the mechanical radiant energy that is transmitted by __________ pressure waves.

Answer 28

Sound, longitudinal

Question 29

Hearing loss can occur due to exposure to noise that is above safe limits and damage may be either?

Answer 29

Temporary or permanent

Question 30

______ is the maximum displacement of an object from its position of rest.

Answer 30

Amplitude

Question 31

At how many decibels do humans normally speak?

Answer 31

65 dB