# Size of Bullet Hole: Comparing 0.000001c & .9c

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• sqljunkey
In summary, the question asks about the size of holes created by bullets traveling at different speeds through a tin foil square target. Assuming the principles of general relativity apply and there are only two objects with masses in the spacetime, the holes would be the same size. However, if the bullets are traveling perpendicular to the target, there may be slight elongation due to lateral motion. Modeling this scenario would require advanced technology and is beyond the scope of this discussion.
sqljunkey
If I had two bullets one moving 0.000001 c and the other moving at .9 c for example, and they both went thru a tin foil square target, assuming they are traveling in vacuum, and that the tin foil square target will make a perfect aperture around the radius of the passing bullet, assuming the bullet is cylindrical in shape, which bullet hole would be the bigger one?

Here I'm assuming there are only two objects (with masses) in the spacetime, and I'm assuming that the principles of general relativity apply.

sqljunkey said:
If I had two bullets one moving 0.000001 c and the other moving at .9 c for example, and they both went thru a tin foil square target, assuming they are traveling in vacuum, and that the tin foil square target will make a perfect aperture around the radius of the passing bullet, assuming the bullet is cylindrical in shape, which bullet hole would be the bigger one?

Here I'm assuming there are only two objects (with masses) in the spacetime, and I'm assuming that the principles of general relativity apply.
The holes would be the same size.

sqljunkey said:
Are you trying to ask whether the diameter of the bullet changes? If so, the answer is no. Length contraction is along the direction of movement.

As long as the bullets are traveling perpendicular to the target, the holes should be the same size.

pervect said:
As long as the bullets are traveling perpendicular to the target,
Good point, but is this restriction the correct one? Isn't the requirement that the target have no component of velocity perpendicular to that of the bullet? If that is not the case then the bullet hole would be elongated slightly due to the lateral motion - and this would depend on the length of the bullet in the rest frame of the foil.

He says GR, not SR. As such, I have no idea what he's getting at.

sqljunkey said:
I'm assuming there are only two objects (with masses) in the spacetime, and I'm assuming that the principles of general relativity apply.

If you are trying to actually model this scenario as the bullet and the foil having enough stress-energy to curve spacetime, sorry, that's way beyond what we can do here. You need a supercomputer and a lot of time.

If you really meant special relativity, i.e., you are fine with spacetime being flat and you are just asking what the Lorentz transformation says about your question, you already have been given the answer in this thread.

In either case, it is time to close this thread.

## 1. What is the significance of comparing bullet holes at different speeds?

Comparing bullet holes at different speeds can provide insight into the effects of velocity on the size and shape of the hole. This can help in understanding the physics of bullet impact and can also have practical implications for forensic investigations.

## 2. How do you measure the size of a bullet hole?

The size of a bullet hole can be measured by using a caliper or ruler to measure the diameter of the hole. Alternatively, a microscope can be used to measure the diameter of the hole more accurately.

## 3. What is the difference between 0.000001c and 0.9c?

0.000001c is a very slow speed, approximately 0.0003 meters per second, while 0.9c is a much faster speed, approximately 270,000,000 meters per second. This is a significant difference in velocity and can have a major impact on the size of the bullet hole.

## 4. Can a bullet hole be larger at higher speeds?

Yes, a bullet hole can be larger at higher speeds. As the velocity of the bullet increases, the kinetic energy also increases, resulting in a more forceful impact and potentially a larger hole.

## 5. What other factors can affect the size of a bullet hole?

The size of a bullet hole can also be affected by the type and shape of the bullet, the material and thickness of the target, and the angle at which the bullet impacts the target. Additionally, environmental factors such as air resistance and temperature can also play a role in the size of the bullet hole.

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