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How to Calculate the G Forces of Moving Mass

Despite its name, the g-force is actually a measure of acceleration as compared to standard acceleration in freefall. Neglecting air resistance, any object near Earth's surface falls with a constant acceleration of 9.81 meters per second squared, so one g (sometimes called one gee) is equal to 9.81 m / s^2. If you are standing on the ground, for example, you are experiencing a net g-force of 1 g, because the ground pushes back up on you with enough force that your net acceleration is 0. If you are in freefall, by contrast, you feel weightless because you are experiencing a net g-force of 0.

Instructions

- 1
  Determine the object's horizontal acceleration. If a dragster goes from 0 mph to 200 mph in 10 seconds, for example, and its acceleration over this time period is constant, then its acceleration is equal to the change in velocity divided by the time. It's best to convert to meters per second here, since acceleration due to gravity uses units of m / s^2, so if you multiply 200 mph by 1609 meters per mile, then divide by 3,600 seconds per hour, you have a final velocity of 89.4 meters per second. Dividing this by the time taken to accelerate to this speed gives an acceleration of 89.4 / 10 = acceleration 8.94 meters per second squared.
- 2
  Divide the horizontal acceleration by 9.81 m / s^2 to obtain the horizontal g-force. 8.94 / 9.81 = 0.911 g.
- 3
  Determine what vertical acceleration the object experiences relative to the acceleration it would normally experience in freefall. If you were in freefall, for example, your acceleration would be -9.81 m / s^2, so if you are standing on the ground and not falling, your acceleration is +9.81 m / s^2 greater than it would be in freefall.
- 4
  Divide the vertical acceleration by 9.81 m / s^2 to obtain the vertical g-force. The dragster remains on the ground throughout, so the vertical g-force is 1 g.
- 5
  Use the Pythagorean Theorem to find the net g-force the driver will experience. From the theorem, the net g-force will be equal to ( (horizontal g-force squared) + (vertical g-force squared) )^1/2. In the case of the dragster, for example, it will be ( (0.911)^2 + 1^2 )^1/2, which is 1.353, so this is the net g-force experienced by the driver.

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