# How Fast Must a Truck Travel to Knock a Motorcycle 3 Feet Away?

• Bill Benedict
In summary, the conversation discusses an incident where an insured driver backed up and hit a motorcycle, causing damage. The question is posed as to what speed the truck would have to be going to knock the motorcycle 3' beyond the bumper. However, this question is difficult to answer without further analysis and expert knowledge, as real-life impacts are complex and variable. The speaker is seeking help in fighting the insurance company's refusal to cover the damages.
Bill Benedict
I know an exact answer is impossible but an estimate will prove the following statement impossible. Allstates insured driver said he backed up hit my sons motorcycle, did not feel the impact, and stopped when he heard it hit the ground. He parked and got out and the motorcycle was 3' from the rear bumper of the truck.
What speed would the 6025lb truck have to be going to knock the 550lb motorcycle 3' beyond the bumper of the truck. I know he would have to be traveling at a rate of speed much higher than he was and I'm looking for numbers to prove it to the insurance company.
My belief on what happened. If he was backing up at 5mph then he is traveling 7.3" per second. It takes a 36" object .43 seconds to fall (without the impact). He didn't stop until he heard the impact which means he would have traveled 3.1' before he stopped. His rear tire is 30" from his bumper proving his rear tire would have ran onto the rear tire of the motorcycle. Does this make sense?
Sorry I'm not a physicist or mathematician just an elementary teacher trying to fight the insurance company to cover the damages to my sons motorcycle.
Any help is greatly appreciated.

Last edited by a moderator:

That question is impossible to answer without a detailed analysis. There are experts for this, and the insurance won't take "someone on the internet said this!" seriously.

- real-life impacts are not collisions between point-like or spherical objects
- reaction times of drivers are variable
- motorcycles are not falling down vertically. If they start close to the balanced position, they can need a long time to hit the road with the side.
- after hitting the road, motorbikes can still move

Bill Benedict

## 1. What is meant by "impact speed"?

Impact speed refers to the velocity at which two objects collide with each other. It is a measure of the energy and force involved in the impact.

## 2. How is impact speed determined?

Impact speed can be determined using various methods such as analyzing the damage caused by the impact, calculating momentum and energy equations, or using specialized equipment like radar guns or high-speed cameras.

## 3. Why is it important to determine impact speed?

Determining impact speed is important because it helps us understand the severity of an impact and its potential consequences. It is also crucial in accident investigations and for designing safety measures.

## 4. What factors can affect impact speed?

The factors that can affect impact speed include the velocity and mass of the objects involved, the angle and direction of impact, and any external forces such as friction or air resistance.

## 5. Are there any limitations to determining impact speed?

Yes, there are limitations to determining impact speed depending on the method used. For example, analyzing damage may not be accurate if the objects involved are not solid, and using equations may not account for all external factors. Also, in some cases, the exact impact speed may not be able to be determined due to lack of evidence or complexity of the impact.

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