People are often confused about the difference between weight (mass) and force. Sizes measure weight (mass) in pounds (lb) or kilograms (kg), etc. Force gauges, on the other hand, measure force in Newtons. (In the us, other units such as lbf, ozf and kgf are also available. ) One Newton is described as the force needed to accelerate 1 kilogram of mass at the rate of 1 meter per second every second. You can feel this one Newton force by putting a small apple (100 g) on your palm.

The apple’s weight (mass) is constant anywhere in the universe. When dropped, it falls freely to the Earth. In outer space, instead of falling it floats, even though its weight (mass) is unrevised. What causes the apple to fall or float? The force caused by the object’s weight (mass*) and gravity velocity, or as derived from Newton’s Second Law of Motion: force = mass times velocity.

On earth the apple falls at a continually increasing rate of speed called gravity velocity. Gravity velocity varies above latitude, degree of lift and other factors. Gravity velocity at 45 degrees latitude, sea level is 9. 80665 m/S2. In 1901, the typical Conference on Weights and Measures set 9. 80665 m/S2 as the standard International Gravity Velocity value. gravityAcceleration

To are the cause of the deviation in gravity velocity at different latitudes and elevations, sizes need to Digital Force Gauge calibrated at and used at their location. A small apple assessed on a scale calibrated in Rome does not measure the apple’s correct weight in New york.

Force gauges, once calibrated for local gravity acceleration*, will measure the correct force values anywhere in the universe. A 100-lb weight (mass) may produce more or less force than 100 lbf due to the deviation in local gravity velocity. A 100-lb weight (mass*) produces 100 lbf force only at the International Gravity Velocity value of 9. 80665 m/S2.

The formula for local force (lbf) produced by a 100-lb weight (mass*) is calculated as below: