Metric Horsepower per Square Foot [hp(metric)/ft²]

The unit metric horsepower per square foot, written as hp(metric)/ft², measures power or energy flux density per unit area using metric horsepower. One metric horsepower is defined as 735.5 watts, slightly less than the mechanical (Imperial) horsepower of 745.7 W. Dividing by square feet gives the rate of power delivery or absorption per unit area.

This unit is used in engineering, industrial design, and energy flux studies where power distribution per unit surface area is analyzed. Applications include:

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  Mechanical equipment power output per platform area

  
  
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  Energy flux in industrial processes

  
  
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  Assessment of high-power machinery energy delivery

  
  

Mathematically, the power flux can be expressed as:

where q is power per unit area (hp(metric)/ft²), P is power in metric horsepower, and A is area in ft².

Conversion to SI units:

While W/m² is the SI standard, hp(metric)/ft² is convenient in regions using metric horsepower, especially in European engineering and historical industrial literature, providing an intuitive measure of high power density per unit surface area.

Dyne per Hour per Centimeter [dyne/(h·cm)]

The unit dyne per hour per centimeter, written as dyne/(h·cm), measures force per unit length over time, often used in contexts such as viscous drag, material creep, or very slow mechanical processes in cgs (centimeter-gram-second) units.

A dyne is the cgs unit of force, defined as the force required to accelerate 1 gram of mass by 1 cm/s². Therefore, 1 dyne = 10⁻⁵ newtons in SI units. The additional division by centimeter represents a per-unit-length measure, and division by hour accounts for time rate.

Mathematically, the quantity can be expressed as:

where F is force in dynes, L is length in cm, and t is time in hours.

Applications include:

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  Creep or stress studies in materials under very small forces over long periods

  
  
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  Lubrication or viscous flow measurements in cgs-based engineering studies

  
  
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  Experimental mechanics where small forces per unit length are measured over extended time

  
  

Conversion to SI units:

This unit is largely of historical or specialized interest but provides a precise cgs-based measure for extremely slow, small-force phenomena.