How Gravity Variations Impact Force Measurement

Last week, we went over the basics of dynamometers and some of their applications. These tools have diverse applications; they can measure torque, power, and force. If you intend to use dynamometers to measure force, you should know a little about how differences in locational gravity can impact the readings you receive. Today, we’ll explain how gravity variations affects weighing and force measurement applications and why it matters.

How Gravity Variations Impact Force Measurement

Gravity variations can have big implications for weighing and force measurement. Here’s how.

What Is Local Gravity?

If you calibrated a scale in Seattle, then brought it with you on a trip to Tokyo and weighed an object of known mass, what you notice might surprise you. You might think that the object somehow became lighter.

Of course, this is not really the case. The reason you will get a marginally lighter reading in Tokyo is due to differences in local gravity. Again, the difference you notice will be extremely small, but it can be significant enough to matter depending on your industry and application.

The force of gravity is stronger in Seattle than it is in Tokyo. Wherever you travel in the world, you need to know the local gravity to perform proper force measurement. Here are a few of the factors that impact on-site gravity:

  • The moon’s orbit
  • Altitude
  • The earth’s rotation (centrifugal force)

If you want to find your local gravity, there are plenty of tools on the internet that make this easy. Try this one out. You just have to know your local latitude, longitude, and elevation.

Why Does it Matter for Force Measurement?

Now, let’s take a look at how gravity variations impact force measurement. Earlier, we used the example of a scale being calibrated in Seattle and moved to Tokyo. While it’s true that this would yield different readings, this issue isn’t too hard to resolve. All you have to do is calibrate once more with a known weight. Keep in mind that generally remain fixed in the same location.

Let’s review three factors that are taken into account when measuring force: the density of the air, density of the material, and gravity. Because gravity changes across the earth’s surface, you need to take this into account while performing force measurement. Failure to do so can lead to significant discrepancies in the reading displayed on your dynamometer.

For force measurement to be as accurate as possible, you should establish the on-site gravity of your laboratory or location where you are weighing.  Crane scales and dynamometers are generally manufactured without knowledge of the local gravity where the tool will be used. Keep this in mind the next time you acquire a new force measurement instrument!


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This entry was posted on Friday, January 22nd, 2021 at 12:50 pm. Both comments and pings are currently closed.

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