SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
SLHS 1301W Lab 1 Unit Conversion
Learning Objectives
Upon successful completion of the lab, you will be able to
1. describe the physical quantities needed for speech acoustics such as distance,
intensity, power, force, pressure, frequency, and period.
2. perform unit conversions between different units of measurement and properly use
metric prefixes.
Interactive Exercises
Follow lab instructor’s direction to use the interactive software for the unit conversion and
prefix exercises.
Exercise 1: Distance (length; MKS and cgs metric systems)
1 in. = 2.54 cm
1 ft = .333 yd
1 mi. = 1.609 km
1 cm = .3937 in
1 yd = 3 ft
1 km = 0.6215 mi
1 ft = 0.3048 m
1 yd = .9144 m
1 m = 3.281 ft
1 m = 1.0936 yd
Exercise 2: Power
Power is the amount of energy/s. Power is ordinarily expressed in watts. In the MKS system,
energy is expressed in joules. Because power is energy/s, the unit of measure can also be joules/s.
1 watt = 1 joule/s
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
In the cgs system, energy is expressed in ergs, where 1 joule = 10,000,000 (107) ergs and 1 erg =
.0000001 (10-7) joules. Thus, power also can be expressed in ergs/s.
In the fps system, power is expressed in horsepower. Because energy is expressed in foot
pounds, power can be expressed in foot pounds per sec.
1 hp = 550 ft lb./s
1 hp = 0.7457 kw
Exercise 3: Intensity
We learned in the last exercise that Power is the amount of energy/s. Intensity is the amount of
power (energy/s) spread over some standard area, the m2 (MKS) or cm2 (cgs). Power is
expressed in watts, and intensity therefore is expressed in watt/m2 (MKS) or watt/cm2 (cgs).
Power also can be expressed in milliwatts (mwatt), and intensity then would be expressed in
mwatt/m2 (MKS) or mwatt/cm2 (cgs).
1 m = 100 cm
1 mwatt = .001 watt
and
and
1 cm = .01 m (reciprocal, 1/x)
1 watt = 1000 mwatt (reciprocal)
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Exercise 4: Force
A force is a push or a pull. In the MKS system, force is expressed in newtons (N), where 1 N is
the force required to accelerate a mass of 1 kg from a velocity of 0 m/s to a velocity of 1 m/s in 1s:
1 N = 1 kg x 1 m/s2.
In the cgs system, force is expressed in dynes: 1 dyne = 1 g x 1 cm/s2.
1 N = 100,000 (105) dynes.
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Exercise 5: Pressure
Pressure is the amount of force per unit area (p= F/A). In the MKS metric system, force is
expressed in newtons (N), and pressure (p) therefore is expressed in newtons/m2 (N/m2) or
pascals (Pa), where 1 N/m2 = 1 Pa. In the cgs metric system, force is expressed in dynes, and
pressure therefore is expressed in dynes/cm2. The equivalencies among those three are:
1 N/m2 = 1 Pa = 10 dynes/cm2.
Note: In the MKS metric system, pressure also can be expressed in micronewtons/m2 or in
micropascals (µN/m2 or µPa).
1 µN/m2 = 10-6 N/m2, and
1 µPa = 10-6 Pa, and
1 N/m2 = 1 Pa
Exercise 6: Metric Prefixes and Units of Measure for Frequency and Period
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SLHS 1301W
Tera
Giga
Mega
Kilo
Hecto
Deka
Base Value
Deci
Centi
Milli
Micro
Nano
Pico
The Physics and Biology of Spoken Language
Professor Yang Zhang
Metric Prefixes
Symbol
1012
109
106
103
102
101
100
10-1
10-2
10-3
10-6
10-9
10-12
T
G
M
k
h
da
(base value; e.g., m, Hz, s, etc.)
d
c
m
µ
n
p
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
times the base value
1. To convert from one unit value to another with a larger exponent, divide.



(Divide by 103)
(Divide by 106)
(Divide by 103)
1000 Hz = 1 kHz
1,000,000 Hz = 1 MHz
1 ms = 0.001 s
2. To convert from one unit value to another with a smaller exponent, multiply.




(Multiply by 103)
(Multiply by 103)
(Multiply by 103)
1 kHz = 1000 Hz
1 MHz = 1,000,000 Hz
0.001 s = 1 ms
Units of Measure for Frequency (f) and Period (T)
Frequency (f) refers to the number of cycles completed per second (c/s). The base value is
expressed in hertz (Hz). Thus, a frequency of 1 Hz means that we complete 1 cycle each second,
and 200 Hz means that we complete 200 cycles each second. A frequency of 1 Megahertz
therefore corresponds to 1,000,000 (106) Hz.
Period (T) refers to the number of seconds required to complete one cycle (s/c). The base value
is expressed in seconds (s). Thus, a period of 2 s means that we require 2 s to complete one cycle.
A period of 1 millisecond (1 ms) means that one cycle is completed in 1/1000 (10-3) of a second.
Frequency is the inverse (the reciprocal) of period (f = 1/T), and period is the inverse of
frequency (T = 1/f). For example,


If f = 200 Hz, T = 0.005 s, or 5 ms
and
If T = 0.001 s, f = 1000 Hz, or 1 kHz.
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Lab 1 Units Conversion: Distance
Name: _________________________________ Date:
Equation 1: in. to cm
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Equation 2: cm to in.
in.
cm
cm
in.
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Equation 3: ft to yd to m
ft
yd
m
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mi.
km
mi.
km
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Equation 4: mi. to km
How would you convert from km to mi.? _____________________________________________
How would you convert from mi to yd.? _____________________________________________
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Lab 1 Unit Conversion: Power
Equation 1: watts to joules/s
What is the conversion factor? ________________________________________________________
watt
joules/s
watt
joules/s
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Equation 2: watts to ergs/s
What is the conversion factor? ________________________________________________________
watts
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ergs/s
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watts
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ergs/s
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Equation 3: horsepower to ft lb./s
hp
ft lb./s
hp
ft lb./s
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Equation 4: horsepower to kwatts
Note: 1 hp = 0.7457 kw
Conversion: hp x 0.7457 OR
hp
kwatts
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hp/1.341
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Lab 1 Unit Conversion: Intensity
Equation 1: watt/m2 to watt/cm2
What is the conversion factor? ______________________________________________________
watt/m2
watt/cm2
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Equation 2: watt/m2 to mwatt/cm2
What is the conversion factor? _______________________________________________________
watt/m2
mwatt/cm2
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Lab 1 Unit Conversion: Force & Pressure
Equation 1: N to dynes
N
dynes
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What would be the conversion factor if you wish to convert from dynes to newtons?
____________________________________________________________
Equation 2: Convert N/m2 to dynes/cm2.
N/m2
dynes/cm2
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If you were given pressure in dynes/cm2, how would you convert to N/m2? _______________________
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SLHS 1301W
The Physics and Biology of Spoken Language
Professor Yang Zhang
Lab 1 Unit Conversion: Metric Prefixes
and
Frequency and Period
FREQUENCY
Equation 1: Hz to daHz
Equation 2: Hz to hHz
Hz
daHz
Hz
hHz
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Equation 3: Hz to kHz
Equation 4: Hz to MHz
Hz
kHz
Hz
MHz
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Equation 5: Hz to GHz
Hz
GHz
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PERIOD
Equation 1: s to ds
Equation 2: s to cs
s
ds
s
cs
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SLHS 1301W
The Physics and Biology of Spoken Language
Equation 3: s to ms
Professor Yang Zhang
Equation 4: s to µs
s
ms
s
µs
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Equation 5: s to ns
s
ns
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The following exercises do not appear on the computer screen.
calculator.
Equation 1: f in Hz to T in s
Use either your pocket calculator or the PC
Equation 2: f in Hz to T in ms
f
T
f
T
1000
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1000
________
1250
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1250
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766
_______ _
766
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Equation 3: T in s to f in Hz
Equation 4: T in s to f in kHz
T
f
T
f
.0025
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.0025
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.0038
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.0038
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.0105
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.0105
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Equation 5: T in ms to f in Hz
Equation 6: T in ms to f in MHz
T
f
T
f
1.5
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1.5
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3
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3
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.2
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.2
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