Physical Sound - Elementary Physics

Question 1

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In the subject of mechanics, what is the symbol given to energy?

Answer 1

E

Question 2

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In the subject of mechanics, what is the unit of measure for energy? What is the symbol for this unit of measure?

Answer 2

The joule (J)

Question 3

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A moving object possesses what type of energy?

Answer 3

Kinetic

Question 4

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A hot body possesses what type of energy?

Answer 4

Thermal

Question 5

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Batteries, fuel, or food all possess what type of energy?

Answer 5

Chemical potential

Question 6

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A compressed spring possesses what type of energy?

Answer 6

Potential

Question 7

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Can the measurement of energy be determined directly?

Answer 7

No, the measurement of energy can only be determined by observing changes in energy.

Question 8

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In the subject of mechanics, what is the symbol given to force?

Answer 8

F

Question 9

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In the subject of mechanics, what is the unit of measure for force? What is the symbol for this unit of measure?

Answer 9

Force is measured in Newtons, written N.

Question 10

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What does Newton’s third law of motion say about force?

Answer 10

Whenever an object A exerts a force on another object B, then B will exert an equal force in the opposite direction on A.

Question 11

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What is the condition when two forces are balanced?

Answer 11

Equilibrium

Question 12

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When a force acts on a surface, the surface experiences what?

Answer 12

Pressure

Question 13

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What is a symbol for pressure?

Answer 13

p

Question 14

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What is the unit of measure for pressure? What is the symbol for this unit of measure?

Answer 14

The Pascal (Pa)

Question 15

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What is a formulaic expression of pressure?

Answer 15

One Pa = 1N/m2

or pressure equals force divided by area:

Question 16

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When energy moves, it can be harnessed or channeled to do what?

Answer 16

Work

Question 17

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In the subject of mechanics, what is the unit of measure for work? What is the symbol for this unit of measure?

Answer 17

Joules (J)

Question 18

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Work is a change of what?

Answer 18

Energy

Question 19

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What is the formulaic expression for work as a change of energy?

Answer 19

W = ΔΕ

Question 20

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Our ears or a microphone observe sound as what?

Answer 20

Changing energy patterns

Question 21

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In the subject of mechanics, what is the unit of measure for power? What is the symbol for this unit of measure?

Answer 21

watts (W)

Question 22

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Power is the rate of what?

Answer 22

The rate at which work is done

Question 23

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What is the relationship between a watt and a joule?

Answer 23

One watt is the same as one Joule per second (1J/s) or how much energy changes state each second.

Question 24

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In an electronic amplifier with loudspeakers, sound is produced from electrical energy. What is the output, in Joules, of a perfect 10W amplifier and loudspeaker?

Answer 24

10 Joules of electrical energy are converted to sound every second.

Question 25

# Designing Sound by Andy Farnell What does the second law of thermodynamics have to do with sound?

Answer 25

Every sound we hear is caused by energy doing work and a part of all energy moving from a higher state to a lower state.

Question 26

# Designing Sound by Andy Farnell Why are Newton's laws of motion important to understanding physical sound?

Answer 26

They ultimately explain how air moves to make sound.

Question 27

# Designing Sound by Andy Farnell What is the formulaic expression for work done when a mechanical force produces movement for a distance?

Answer 27

*W* = *F* x d

Question 28

# Designing Sound by Andy Farnell What is the symbol for velocity?

Answer 28

The symbol *v*

Question 29

# Designing Sound by Andy Farnell What is the unit of measure for velocity? What is the symbol for this unit of measure?

Answer 29

Velocity is measured in meters per second, written m/s.

Question 30

# Designing Sound by Andy Farnell What is the symbol for acceleration?

Answer 30

The symbol *a*

Question 31

# Designing Sound by Andy Farnell What is the unit of measure for acceleration? What is the symbol for this unit of measure?

Answer 31

Acceleration is measured in meters per second per second, written ms^-2.

Question 32

# Designing Sound by Andy Farnell What does Newton's second law of motion state? State the formulaic equation.

Answer 32

Force equals mass times acceleration. *F* = *ma*

Question 33

# Designing Sound by Andy Farnell In addition to mechanical force, what forces in the everyday phenomena of human experience (non-nuclear), can accelerate objects or cause them to move?

Answer 33

Gravity and electromagnetism (magnetism and electricity).

Question 34

# Designing Sound by Andy Farnell Tiny disturbances in the position of molecules are responsible for sound. How are displacement, movement, and freedom related?

Answer 34

* Displacement is the distance and direction (vector) from the rest point or equalibrium position of an object. * Movement is translational (changing position up, down, left, right, forward, or backward) or rotational (changing attitude of pitch, roll, or yaw). * The degree of freedom is determined by the number of directions something can move.

Question 35

# Designing Sound by Andy Farnell What is an excitation point?

Answer 35

The place where power is transmitted to an object.

Question 36

# Designing Sound by Andy Farnell What is an example of an excitation point?

Answer 36

* The scraping of a bow on a violin string * Plucking a guitar string * Hitting a drum with a stick * Blowing through a brass instrument * A bat hitting a baseball * A metal wand placed in the magnetic field of a Theramin