How many Newtons would it take to damage a car?

Click For Summary

Discussion Overview

The discussion revolves around the amount of force required for one car to damage another car of the same model, focusing on scenarios such as head-on collisions and the factors influencing damage. Participants explore various aspects including theoretical calculations, practical observations, and engineering considerations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that in a head-on collision, if the lengths of the cars are compressed by 2 m, damage occurs.
  • Others propose that the speed of the cars and their weight can be used to calculate the mean deceleration and the force required to halt them.
  • One participant notes that crash tests conducted by professionals account for many unknowns, indicating that predicting damage through physics alone is insufficient.
  • Another participant mentions that the glass and door panels of a car can be damaged with relatively little force, suggesting that even minor impacts can cause damage.
  • It is argued that the distribution of force over an area and the time derivative of the force are critical factors in predicting damage, rather than force alone.
  • Some participants recommend considering different objects or materials to study deformation characteristics, as they may provide clearer insights.
  • There is a discussion about the importance of pressure at a specific point on the car, with examples of how a small force can cause damage if concentrated appropriately.

Areas of Agreement / Disagreement

Participants express multiple competing views on the factors influencing car damage, including the role of force, pressure, and the specifics of collision scenarios. The discussion remains unresolved with no consensus reached.

Contextual Notes

Participants highlight limitations in predicting damage due to the complexity of variables involved, such as unknown material properties and the dynamic nature of collisions.

Alexander Baine
Messages
4
Reaction score
0
I am working on a science project, just in my spare time, and for this project I needed to know the amount of force it would take one car to damage another car, but the same model (so same weight, strength etc.) thanks for you help

~ Alex
 
Physics news on Phys.org
Say we are speaking of a head-on collision. If the lengths of the cars are compressed 2 m, the cars are damaged.

Say the speed of the cars is 100 km/h and the weight of the cars is known, you can calculate the mean decelleration and thus the force needed to bring them to a halt.
 
Alexander Baine said:
I am working on a science project, just in my spare time, and for this project I needed to know the amount of force it would take one car to damage another car, but the same model (so same weight, strength etc.) thanks for you help
Professionals do this with crash tests. You cannot do it with physics. There are too many unknowns. It is an engineering problem. After a head-on crash that appears to result in no damage, energy absorbing bumpers may, in fact, have suffered irreversible changes. The next crash may not be as pretty.
 
  • Like
Likes   Reactions: billy_joule
Hesch said:
If the lengths of the cars are compressed 2 m, the cars are damaged.
"Damaged" is a bit of understatement here.
 
  • Like
Likes   Reactions: billy_joule
Say we are speaking of a head-on collision. If the lengths of the cars are compressed 2 m, the cars are damaged.

Say the speed of the cars is 100 km/h, the weight of the cars is known, you can calculate the mean decelleration and thus the force needed to bring them to a halt.

Sorry, I don't think I have posted the above, which is just a repetition of #2. Some technical error ?
 
Last edited:
Which part of the car is easiest to damage? The glass should be pretty easy, but I'm guessing that I can get a door panel to buckle by just pressing hard enough on it manually in the middle. If not, I'm sure I can do it by kicking. Better yet, I can "key" a car with almost no effort at all. So, if a one car scrapes the other car with virtually no force, damage will be done. Does this answer your question?
 
Last edited:
Force by itself is not going to be enough to predict damage. It depends on the area that the force is spread over, and it also depends on the time derivative of the force. (A constant force can't cause vibration, whereas a varying force can.)
 
What not use a different object...something other than a car...
Perhaps you can find a table that shows deformation characteristics of some simplier objects...a quick search did not turn up anything exciting.

I know different construction materials are rated for various loads...say 2" x 4" studs or 4" x4" posts [typically wood]. And I'm sure lally columns are similarly rated...

You might consider, for example, firing a pair of 2" x4" x8ft' pieces of lumber at each other and seeings if you can estimate some small initial deformations...

https://en.wikipedia.org/wiki/Compressive_strength

How far must a basket ball be dropped to deform 1" ? I have no idea; but you could could try figuring it out assuming a vacuum so there is no air resistance slowing it down...
 
I expect the pressure at a given point of the car is more important than the force. I know (I have seen it) that it is possible to drive an awl through the bodywork by force of hand alone. The same force applied to a large object (say the hand itself) does almost no damage.
 
  • #10
Svein said:
I expect the pressure at a given point of the car is more important than the force. I know (I have seen it) that it is possible to drive an awl through the bodywork by force of hand alone. The same force applied to a large object (say the hand itself) does almost no damage.
This is pretty much the same thing bcrowell said in post #7 and is also similar to what I said in post #6 when I talked about "keying" a car.
 
  • #11
Chestermiller said:
This is pretty much the same thing bcrowell said in post #7 and is also similar to what I said in post #6 when I talked about "keying" a car.
Sorry. Sloppy reading.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
16K
  • · Replies 95 ·
4
Replies
95
Views
7K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 46 ·
2
Replies
46
Views
11K
  • · Replies 58 ·
2
Replies
58
Views
9K
  • · Replies 29 ·
Replies
29
Views
3K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 66 ·
3
Replies
66
Views
6K