How to Calculate Negative G's
When you accelerate in a car, take off in an airplane or ride in an elevator, you can feel the forces associated with those vehicles pushing and pulling on you. These forces can be measured and calculated in terms of g--the acceleration due to gravity, which is 9.8 meters per square second (m/s^2). According to Isaac Newton, every action has an opposite and equal reaction, so when an airplane seat pushes on your body and accelerates it, you push back. The force with which you push back is called the negative force and can be measured in negative g's, because it is in the opposite direction of the airplane's force. Negative g's are commonly experienced in cases of deceleration, as is the case when you apply the brakes in a car.
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Instructions
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1
Examine the situation for which you wish to calculate the negative g's. For example, imagine that you are driving a car at 60 mph and you slam on the brakes, causing you to stop in 1 second. Determine how many negative g's that would generate.
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2
Convert mph into meters per second (m/s). Do so by multiplying the mph value by 0.45, a conversion factor based on the fact that there are 1,609 meters in a mile and 3,600 seconds in an hour.
Example: 60 mph x 0.45 = 27 m/s
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3
Calculate the acceleration that you have experienced in the situation you are examining. Do so by subtracting your initial speed from your final speed and then dividing the result by the time it took the speed to change.
Example: (0 m/s - 27 m/s) / 1 s = -27 m/s^2
Notice the the acceleration calculated here is negative because it is 'deceleration.'
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4
Divide the result from Step 3 by the acceleration due to gravity.
Example: -27 / 9.8 = -2.8 m/s^2
Because your deceleration is -2.8 times the acceleration due to gravity, you would say that you experienced an acceleration of negative 2.8 g's.
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References
- Photo Credit jet 3 image by Joshua Peterson from Fotolia.com
