# Car Crash Calculator

Our car crash calculator will obtain the g-force acting on the passengers of a car during a collision.

This tool can work as a:

- Impact force calculator;
- G-force calculator;
- Stopping time calculator; and
- Deceleration calculator.

Keep reading while we explain how to calculate impact force on a car crash using the impact force equation!

## Impact force definition and equation

Before using the car crash calculator, we need to explain some definitions, for example, **impact force**.

The impact force is the **total force** exerted on an object during a collision.

Using the **law of conservation of** **energy**, we can easily obtain the impact force equation for any object or person inside a car during a collision.

### Impact force formula

The moment **before the crash**, the car possesses *kinetic energy*, which reduces to zero right **after the collision**. This energy difference is compensated by the **work done by the impact force**:

therefore:

where:

- $F$ is the
*average*impact force during the collision; - $v$ is the car's speed;
- $m$ is the mass of the object; and
- $d$ is the stopping distance, the distance where the car slows down to zero.

We can rewrite this expression using the time of collision $t$, resulting in:

which relates to the impulse and momentum formula.

💡 You can see from both equations that in order to **reduce** the impact force, we should focus on **increasing the time of the collision** or **increasing the distance** (both are equivalent).

## How to calculate impact force using the car crash calculator

Our car crash calculator can estimate the **average impact force** suffered by a passenger on a moving vehicle during a crash.

Although there are a lot of parameters that either **increase** or **reduce** this impact force (type of vehicle, type of collision, etc.), we've added only one parameter to be as general as possible: **the seat belt**.

With that in mind, to calculate the impact force:

- Select if the passenger
**has their seat belt**or**not**. This option will increase the collision time (with a seat belt) or reduce it, increasing the impact force (without a seat belt). - Input the car's
**speed**before the collision. - Input the passenger's
**weight**. - The car crash calculator will output the
**average impact force**,**stopping time**, and**deceleration**.