Some may consider this a strange number to be of importance or meaning to engineers. Some, but not engineers. The engineer knows this number, 9.81, is one to be remembered and, if it didn’t sound too emotional, cherished. Many non-engineers out there may remember what this number represents from their science class in high school.

9.81, combined with the units of meters per seconds squared is the acceleration due to gravity, at the earth’s surface. It shows up in many equations, especially in mechanical engineering, and is represented by the constant “g”. Thus, astronauts and fighter pilots experience g-forces, or forces as if many times the force of gravity. This acceleration due to gravity means that an object falling near the earth’s surface, discounting air resistance, will travel 9.81 meters per second faster for every second of falling. I know, fascinating.

Sure, we could also talk about 32.2, the English equivalent of “g”, with the units of feet per seconds squared, but let’s not ruin the engineer’s enjoyment of this constant by bringing in a sub-standard unit of measurement. (Thanks.)