# Calculating Car Collision Distance at 30 "g's"

• candycooke
In summary, the distance over which the front end of the car must be designed to collapse in order for a person wearing an over-the-shoulder seat belt to have a good chance of surviving a car collision is dependent on the deceleration not exceeding 30 "g's" and can be calculated using the equation v^2 = u^2 + 2 a s, where V is the final speed, u is the initial speed, a is acceleration, and s is distance. The sign of the acceleration should be taken into consideration when solving this problem.
candycooke
A person who is properly constrained by an over-the-shoulder seat belt has a good chance of surviving a car collision if the deceleration does not exceed 30 "g's" (1.00 g = 9.80 m/s^2). Assuming uniform deceleration at this rate, calculate the distance over which the front end of the car must be designed to collapse if a crash brings the car to rest from 100km/h.

I'm not sure how to get this problem started, any help would be greatly appreciated.

Acceleration is just change in speed divided by time.
You probably want the equation v^2 = u^2 + 2 a s
Where V is the final and u the intial speed, a is acceleration and s is distance.
Be careful about the sign of the acceleration.

I can provide a response to this content by breaking down the problem and explaining the steps to calculate the collision distance at 30 "g's".

Firstly, it is important to understand that "g's" refers to the acceleration due to gravity, which is 9.80 m/s^2. This means that 30 "g's" would be equivalent to 294 m/s^2.

Next, we can use the formula for motion with constant acceleration, which is distance = (initial velocity)^2 / (2 * acceleration). In this case, the initial velocity is 100 km/h, which can be converted to m/s by multiplying by 1000 and dividing by 3600. This gives us an initial velocity of 27.78 m/s.

Substituting these values into the formula, we get distance = (27.78 m/s)^2 / (2 * 294 m/s^2) = 0.250 m or 25 cm.

This means that in order for a person to have a good chance of surviving a car collision with a deceleration of 30 "g's", the front end of the car must be designed to collapse over a distance of 25 cm. This highlights the importance of car safety features and proper design in protecting passengers during a collision.

It is also worth noting that this calculation assumes uniform deceleration, which may not always be the case in real-life collisions. Other factors such as the type of collision, the weight and speed of the vehicles involved, and the use of additional safety features may also affect the actual collision distance. Therefore, it is important for car manufacturers to conduct thorough safety testing and design their vehicles to withstand a range of possible collision scenarios.

## 1. How is the distance of a car collision at 30 "g's" calculated?

The distance of a car collision at 30 "g's" is calculated using the formula D = 1/2 * a * t^2, where D is the distance, a is the acceleration in "g's", and t is the time in seconds. This formula is based on the laws of motion and is commonly used in physics to calculate the displacement of an object.

## 2. What is the significance of 30 "g's" in car collisions?

The unit "g" stands for gravity and is commonly used to measure acceleration. 30 "g's" means that the car is experiencing an acceleration 30 times that of gravity. This is a high acceleration and can result in severe damage to the car and its occupants.

## 3. What factors can affect the calculation of car collision distance at 30 "g's"?

The calculation of car collision distance at 30 "g's" can be affected by several factors such as the speed of the car before the collision, the weight and design of the car, the road surface, and the type of collision (front, rear, side). These factors can impact the acceleration and time of the collision, which in turn affects the distance calculation.

## 4. Can the calculation of car collision distance at 30 "g's" be used to determine the severity of a car accident?

Yes, the calculation of car collision distance at 30 "g's" can be used to determine the severity of a car accident. Generally, the higher the "g" force experienced during a collision, the more severe the accident and the greater the potential for injury to the car and its occupants.

## 5. Are there any limitations to using the formula for calculating car collision distance at 30 "g's"?

Yes, there are some limitations to using this formula. It assumes that the car is the only object involved in the collision and that the impact is instantaneous. In reality, there may be multiple cars involved, and the impact may occur over a longer period of time. Additionally, this formula does not take into account other factors such as air resistance, which may affect the accuracy of the calculation.

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