# How to calculate the speed of a vehicle on impact

• Lordtrenchard
In summary, if a vehicle hits a stationary object and you know the distance traveled of the object, the weight of the object, the model of the vehicle and that conditions were dry on a tarmac road, it is possible to work out the speed of the vehicle on impact.
Lordtrenchard
A friend posed this question to me tonight.

If a vehicle hits a stationary object and you know the distance traveled of the object, the weight of the object, the model of the vehicle and that conditions were dry on a tarmac road, is it possible to work out the speed of the vehicle on impact?

280 views and no reply?? Is it possible to calculate?

What, no answer in all of an hour and half? There simply isn't enough (and most of what you listed, the model of the vehicle, the condition of the road,etc., is not relevant). Even assuming a "perfectly elastic" impact, you would need to know, for example, how the impact affected the speed of the vehicle- so you could calculate the exchange of energy.

Sorry mate. Was just trying to help out a friend who had property damaged in an RTC. Was just asking if it was possible to get a calculation of whether the vehicle was traveling over the 30Mph limit when it hit his property.

The key problem is knowing what would have limited the distance travelled.
If the object is a ball on a hard level surface, it could travel 100s of metres without too much encouragement.
If, at the other extreme, it was a dead weight that would not be likely to slide or bounce very far then you can put a lower limit on the speed.
Of course, if there is forensic evidence to show where the object first hit the ground, as a distance from the impact location, that will do instead.
The greatest distance for a given speed would correspond to the object's having been launched at 45 degrees to the horizontal. The distance will also be greater if the object had a higher centre of gravity when struck than when it landed.
Can you fill in some of these details?

## 1. How do you calculate the speed of a vehicle on impact?

The speed of a vehicle on impact can be calculated using the formula: speed = distance/time. Time can be measured by the duration of the impact, while distance can be determined by the length of the skid marks or the distance traveled by the vehicle before coming to a complete stop.

## 2. What other factors should be considered when calculating the speed of a vehicle on impact?

In addition to time and distance, other factors that should be considered when calculating the speed of a vehicle on impact include the weight and size of the vehicle, road conditions, and the angle of impact.

## 3. Can the speed of a vehicle on impact be accurately calculated in all situations?

While the formula for calculating the speed of a vehicle on impact is generally reliable, there are certain factors that may impact its accuracy. For example, if the vehicle is traveling on a curved path before impact, the speed calculation may not be as precise.

## 4. Is there a standard method for determining the speed of a vehicle on impact?

Yes, there are several standard methods for determining the speed of a vehicle on impact, including the conservation of momentum method and the energy method. These methods take into account the mass and velocity of the vehicle before and after impact to calculate the speed.

## 5. Can the speed of a vehicle on impact be used to determine fault in a car accident?

The speed of a vehicle on impact can provide valuable information for determining fault in a car accident, but it is not the only factor that should be considered. Other evidence, such as witness testimonies and physical damage to the vehicles, should also be taken into account when determining fault.

Replies
4
Views
1K
Replies
1
Views
691
Replies
6
Views
1K
Replies
6
Views
7K
Replies
2
Views
1K
Replies
7
Views
714
Replies
15
Views
1K
Replies
4
Views
2K
Replies
2
Views
2K
Replies
102
Views
5K