# G Force Calculator

Created by Rahul Dhari
Last updated: Feb 02, 2023

This g force calculator helps determine the force due to gravitational acceleration experienced by a moving object. The tool first establishes the acceleration due to gravity and then computes the gravitational force equivalent based on the moving speed of any entity.

Read on to understand how you can calculate the g force from the velocity of an object.

## What is g force

The g force or g-force, otherwise known as the gravitational force equivalent is the force experienced by an object with reference to the acceleration to due to gravity value — $9.81 \text{ m/s}^2$ or $32.17\text{ ft/s}^2$. The force experienced by an object resting on the earth's surface is roughly $1 g$. Note the $g$ is different from the unit of weight grams ($\text{g}$).

The g force is directly proportional to the object's acceleration, such that a pilot experiences as much as $8 g$ and $-5 g$. When the g value is positive, the pilot's blood rushes towards his feet, leading to blackouts or losing consciousness, whereas, during the negative g value, it causes the blood flow towards the brain and eyes resulting in swelling veins and reddened visions. We can also experience the same rush on roller coaster rides, during which people often lose consciousness. Mathematically, the acceleration due to gravity, $g$ for an object is:

$\scriptsize g = \frac{GM}{r^2}$

where:

• $G$ - Universal gravitational constant, $6.674 \times 10^{-11} \text{ m}^{3} \text{kg}^{-1} \text{s}^{-2}$;
• $M$ - Mass of the celestial body (e.g. planet Earth); and
• $r$ - Radius of celestial body.

## How to calculate g force

If you know the acceleration due to gravity value, you can further calculate the g force from velocity. Suppose an object has an initial velocity $v_0$ and final velocity, $v_1$ over a time interval, $t$. The equation gives the g force:

$g \text{ Force} = \frac {v_1 - v_0}{t g} = \frac {\Delta v}{t g}$

It is interesting to notice that the term $\frac {v_1 - v_0}{t}$ is acceleration of an object.

## Example: Using the g-force calculator.

Estimate the g force on a person suddenly stopping his car (in $1 \text{s}$ that was traveling at a velocity of $60 \text{km/h}$.

To calculate the g force:

1. Enter the initial velocity, $v_0 = 60 \text{ km/h}$ or $16.67 \text{ m/s}$.
2. Fill in the final velocity, $v_1 = 0 \text{ km/h}$.
3. Set the time, $t = 1\text{ s}$.
4. The calculator returns the g value using the equation:
$\qquad \scriptsize g \text{ Force} = \frac {16.67 - 0}{1 \times 9.81} = - 1.697 \ g$

The driver experiences a negative g force value of $-1.697 \ g$ when he suddenly stops his car.

## Other similar calculators

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## FAQ

### How do I calculate g force from velocity?

To calculate g force from velocity:

1. Subtract initial velocity from final velocity.
2. Divide the difference by time.
3. Divide the resultant by the acceleration due to gravity, 9.81 m/s², to obtain the g force value.

### What is the g force if I am driving at a speed of 60 km/h?

Considering the initial velocity as 0 km/h, and time as 1 s, the g force value is: 1.697 g. Mathematically, g force = (v1 - v0) / (t × g) = (16.67 - 0) / (9.81) = 1.697 g.

Rahul Dhari
Gravitational acceleration
Mass (M)
Earths
Distance (r)
ft
Acceleration due to gravity (g)
ft/s²
Linear motion
Initial velocity (V₀)
ft/s
Final velocity (V₁)
ft/s
Time (t)
sec
Gravitational force equivalent (F)
g
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