Now, for the title:What's the Bullet Speed?

In summary, the conversation is about the concept of relative speeds when traveling on a train and shooting a gun in the same or opposing direction of the train's movement. The ground speed of the flying ball is affected by both the train's constant speed and the speed at which it is thrown. Similarly, the ground speed of a bullet shot from the train is also affected by the train's speed and the direction in which it is shot. The formula for adding relative speeds is different in relativity.
  • #1
tellmewhy
1
0
Hi,

I am new to this forum, so please go easy on me.
I wonder about this...

You are traveling in a train at the constant speed of 100 mph. Imagine that you throw a small ball at the speed let say 40 mph. So ground speed of this flying ball is 140 mph (as you already travel at 100mph + speed of thrown ball 40mph. For you in train ball travels at 40 mph, for someone outside the train, standing on ground it travels at 140 mph.

Question...What if you have a gun and you shot from train outside in same direction as train is moving... what is the ground speed of the bullet?

What if you will shoot in opposing direction, what will be speed of bullet?

For the sake of keeping it simple, let's assume that bullet travel at 700mph (9mm has about this speed, all depends from weather, temperature etc..but not important)

While shooting in the same direction as moving train the bullet should travel at 800mph?
(here we should look at 2 options)
1. Shooting inside the train along wagon 800mph
2. Shooting outside the train, taking gun out through the window and shooting same direction as moving train [i think air/wind will slow down initial speed of bullet, etc)

Shooting opposite direction will travel at 600mph?

Just wonder about this, as .. well is interesting.
Hope I will find my answers here.

Thanks for reading
Marcin
 
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  • #2
Welcome to PF!

Hi Marcin! Welcome to PF! :smile:

Yes, that all looks correct …

relative speeds add like vectors (so if they're in directly opposite directions, you subtract the magnitudes).

(but in relativity, of course, the formula for adding relative speeds is different)
 

1. What is the typical speed of a bullet?

The typical speed of a bullet can vary greatly depending on the type of bullet and the firearm it is fired from. However, the average speed of a handgun bullet is around 1000 feet per second (fps), while a rifle bullet can travel at speeds up to 3000 fps.

2. How fast can a bullet travel?

The speed of a bullet can range from 100 fps for a low-powered handgun to over 4000 fps for a high-powered rifle. The exact speed will depend on factors such as the firearm, type of bullet, and atmospheric conditions.

3. What is the fastest bullet speed ever recorded?

The fastest bullet speed ever recorded was achieved by a .220 Swift rifle cartridge, which traveled at a speed of 4665 fps. This record was set in 1935 using a prototype rifle specifically designed for high velocity.

4. Does the temperature affect bullet speed?

Yes, temperature can affect the speed of a bullet. Cold temperatures can cause the gunpowder to burn slower, resulting in a decrease in bullet speed. On the other hand, hot temperatures can cause the gunpowder to burn faster, increasing the bullet speed.

5. Can a bullet travel faster than the speed of sound?

Yes, some bullets can travel faster than the speed of sound, which is approximately 1125 fps. These bullets are known as supersonic bullets and are commonly used in rifles. When a bullet travels faster than the speed of sound, it creates a sonic boom, which can be heard by those nearby.

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