Units of Measurement and Conversions

Units

• 1 Newton (N) = 1 kg*m/s²
• 1 kg = 2.2 lb
• 1 cal = 0.003968 Btu
• 1 cal = 4.187 J
• 1 Btu = 252 cal
• 1 ft/s = 0.3048 m/s
• 1 ft/s = 0.8618 mi/h
• 1 ft/s = 0.5921 knots
• 1 m/s = 3.281 ft/s
• 1 m/s = 2.237 mi/h
• 1 mi/h = 0.4470 m/s
• 1 mi/h = 1.467 ft/s
• 1 knot = 0.5148 m/s
• 1 knot = 1.151 mi/h
• 1 knot = 1.689 ft/s
• 1 lb/cu.ft = 0.01602 cu.cm
• 1 g/cu.cm = 62.42 lb/cu.ft
• 1 g/cu.cm = 1000 kg/cu.m
• 1 kg/cu.m = 0.001 g/cu.cm
• 1 psia = 6.895 kN/m²
• 1 psia = 0.0680 atm
• 1 psia = 27.67 in.H₂O
• 1 bar = 14.5 PSI = 0.98 atm = 760 mm Hg = 105 N/m²
• 1 psia = 51.72 mm Hg
• 1 psig = 14.7 psia
• 1 mm Hg (Torr) = 0.01934 psia
• 16 oz = 1 lb
• 1 g = 1000 mg
• 2.205 lb = 1kg
• 1 ton (US) = 2000 lb
• 1 tonne (Metric ton) = 1000 kg
• 1 dram = 1771.85 mg
• 1 bar = 100 kN/m²
• 1 kN/m² = 0.1450 psia
• 1 bar = 0.9869 atm
• 1 kN/m² = 0.009869 atm
• 1 bar = 1.020 kg/cm²
• 1 Btu/lb/°F = 1 cal/g/°C
• 1 Btu/lb/°F = 4187 J/kg·K
• 1 ppm = 1 mg/L
• 1 mg/m³ = 1 × 10−9 g/cm³
• 1 g/cm³ = 1 × 109 mg/m³
• 1 g/m³ = 62.42 lb/ft³
• 1 lb/ft³ = 0.01602 g/cm³
• 1 British Thermal Unit (Btu) = 1055 J
• 1 faraday = 9.65 × 10⁴ coulombs
• 1 g-cal = 4.19 J
• 1 g-mol at 0°C and 1 atm = 22.4 L
• 1 g-mol at 25°C and 1 atm = 24.45 L
• 1 ampere-hour = 3600 coulombs
• 1 W = 1 J/s = 1 A × 1 V
• 1 kwh = 3.6 × 10⁶ J
• 1 liter = 1000 cm³
• 1 liter = 1000 ml
• 1 m³ = 1000 liter
• 1 liter = 1.06 qt = 61.02 in³ = 0.03531 ft³
• 1 ml = 1 cm³
• 1% by volume = 10,000 part per million (ppm)
• 1 ft³ = 7.5 gallons
• 1 gallon of water = 8.34 lb
• 1 gallon = 3.78 liters
• 1 liter = 61.02 cu in
• 1 hour = 3600 seconds
• 1 kg = 2.2 lb
• 1 lb = 454 gram
• 1 ton (US) =2000 lb
• 1 atm = 14.7 psi = 760 mm Hg = 33.90 ft.H₂O = 760 torr = 101.3 kPa
• 1 calorie = 4.186 Joule
• 1 BTU (British thermal unit) = 1055 Joule
• 1 foot-pound=1.356 Joule
• 1 joule = 1 kg · m/s²
• 1 rad = 10⁻² gray
• 1 rem = 10⁻² sievert
• 1 curie = 3.7x10¹⁰ becquerel
• 1 becquerel = 1 disintegration/sec
• 1 gm/cm³ = 1.94 slugs/ft³ (weight density = 62.4 lb/ft³)
• 1 candela = 1 lumen/steradian
• 1 footcandle = 10.76 candela/m² = 10.76 lux

Physics Formulas

• F = ma/g, m = mass, a = acceleration, g = 9.8 or 32.2 (US)
• F = μN, N = normal force, μ = coefficient of friction
• F₁D₁ = F₂D₂, F = force, D = distance
• ρ = mv, ρ = momentum, m = mass, v = velocity
• v = v₀ + at, v = final velocity, v₀ = original velocity, a = acceleration, t = time
• S = 𝐯₀𝐭 + ½ 𝐚𝐭², 𝐯² =𝐯₀² + 𝟐𝐚𝐬, S = distance, v₀ = initial velocity, a = acceleration, t = time
• W = FS, W = work done, F = force, S = distance
• C² = a² + b² – 2ab cos 0C
• A/SinA = b/Sinb = c/Sinc
• K.E. = ½ mv², K.E. = kinetic energy, m = mass, v = velocity

Statistics

• Histogram: A graph representing the frequency distribution of data.
• Mean: The average value of a data set (ΣXn/n).
• Median: The central value of a data set.
• Mode: The most frequent value in a data set
• Left Skewed: Mean < Median < Mode (longer tails at lower values)
• Right Skewed: Mode < Median < Mean (longer tails at higher values)
• No Skew: Mean = Median = Mode (symmetrical distribution)
• Standard Deviation: A measure of the average distance of data points from the mean.
• Central Tendency: Refers to the mean, median, and mode.
• Coefficient of Variation (CV): Ratio of the standard deviation to the mean (S/Xmean = %).

Hypothesis Testing

• Null Hypothesis (H₀): There is no significant difference between populations, any observed difference is due to sampling or experimental error.
• Type I Error (False Positive, α): Rejecting the null hypothesis when it is true.
  • There is a difference between the means when there is none.
• Type II Error (False Negative, β): Accepting the null hypothesis when it is false.
  • No difference in means, when there is an actual difference.
• F-test: Used to measure the accuracy of sample statistics when comparing them to population parameters.
• Cumulative Error: Accounts for errors in calibration, laboratory procedures, instrument measurement, and correction during sampling.

Accuracy and Precision

• Accuracy: How close a measurement is to the true or accepted value.
• Precision: The consistency of repeated measurements using the same method.

Lower Confidence Limit (LCL)

• Used by OSHA to determine if a measured value exceeds the Permissible Exposure Limit (PEL).
  • If LCL > PEL: Non-compliance
  • If LCL < PEL: Compliance

Area and Volume Formulas

• Rectangle: Area = length * width

• Square: Area = s², where s = side

• Triangle: Area = (1/2) b * h, where b = base and h = height

• Circle: Area = π * r², where r = radius

• Rectangular Solid or Cuboid: V = l×w×h, l = length, w = width, h = height

• Cube: V = a³, where a = length of edge or side

• Cylinder: V = πr²h, r = radius of the circular base, h = height

• Prism: V = B×h, B = area of base, h = height

• Sphere: V = (4⁄3)πr³, r = radius of the sphere

• Pyramid: V = (1⁄3) × B × h, B = area of the base, h = height of the pyramid

Standards

• STP (Standard Temperature and Pressure)
  • Physical Science: 0°C and 1 atm (273.15K and 101.325 kPa)
  • Ventilation: 70°F and 1 atm (21.11°C and 101.325kPa)
  • Industrial Hygiene: 25°C and 1 atm (298.15K and 101.325kPa)
• Density of Water:
  • 1 g/cm³ = 1.94 slugs/ft³
  • Weight Density: 62.4 lb/ft³
  • 1 US gallon of H2O = 8.345 lb
• Angles: 1 radian = 180°/π

Light

• 1 candela = 1 lumen/steradian
• 1 foot-candle = 10.76 candela/m² = 10.76 lux

Magnetic Fields

• 1 tesla = 10,000 gauss

Physical Constants

• Acceleration of gravity = 32.2 ft/s² = 9.8 m/s²
• Velocity of light = 3.0 × 10⁸ m/s
• Planck’s constant = 6.626 × 10⁻³⁴ J·s
• Avogadro’s number = 6.024 × 10²³ /g-mol

Radiation

• 1 rad = 10⁻² gray
• 1 rem = 10⁻² sievert
• 1 curie = 3.7 × 10¹⁰ becquerel
• 1 becquerel = 1 disintegration/s

Key Facts From The Text

• Force and Distance Formula: F₁D₁ = F₂D₂
• Momentum Formula: ρ = mv
• Force Applied at an Angle: F = Nsin angle + μ * N cos angle
• Work Done Formula: W = FS
• Kinetic Energy Variance: Σ(X-Xav)²/N
• Standard Deviation: S = Square Root (X-Xav)²/N
  • 1 std dev = 68% of the data set
  • 2 std dev = 95.45% of the data set
  • 3 std dev = 99.73% of the data set
• Coefficient of Variation (CV): S/Xmean = %
• Relative Standard Deviation (RSD): A measure of dispersion, often expressed as a percentage.
• Cumulative Error: Accounts for various sources of error in air sampling.

Test your knowledge on the various units of measurement and their conversions. This quiz covers everything from Newtons and kilograms to Btu and pressure measurements. Perfect for students in physics or engineering courses.