Effect of Gravity Well on Muzzle Velocity of Gun

In summary, the muzzle velocity of a gun firing a bullet at 1000 m/s horizontally will remain the same when taken deeper into a gravitational well with a higher gravitational redshift factor, as long as both the gun and the observer are free-falling. However, if the gun is not free-falling, the muzzle velocity could be affected due to external factors such as the gun being crushed or friction between the bullet and barrel. This is explained by the equivalence principle, which states that locally, space always has the same properties.
  • #1
yuiop
3,962
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Let's say we have gun that fires a bullet at 1000 m/s horizontally when high up in a gravitational potential.

Now we take the gun deeper into the gravitational well to a point where the gravitational redshift factor is higher by a factor of 4. Will the muzzle velocity be the same, faster or slower as measured by a local observer?THis is related to another thread (https://www.physicsforums.com/showthread.php?t=511699).
 
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  • #2
If the gun is free-falling, and the observer free-falling with it, then the muzzle velocity is the same. This is just the equivalence principle. Locally, space always has the same properties.

If the gun isn't free-falling, then the answer could be different for trivial reasons. E.g., the gun might be instantly crushed by the gravitational field.
 
  • #3
bcrowell said:
If the gun is free-falling, and the observer free-falling with it, then the muzzle velocity is the same. This is just the equivalence principle. Locally, space always has the same properties.

If the gun isn't free-falling, then the answer could be different for trivial reasons. E.g., the gun might be instantly crushed by the gravitational field.

Or a little less extreme, the bullet would have substantial, asymmetric, friction against the barrel.
 

Related to Effect of Gravity Well on Muzzle Velocity of Gun

1. How does gravity affect the muzzle velocity of a gun?

Gravity has a significant impact on the muzzle velocity of a gun. As the bullet is fired, it is affected by the downward force of gravity, causing it to drop towards the ground. This decrease in height leads to a decrease in potential energy, which in turn results in a decrease in muzzle velocity. In other words, the bullet will not travel as far or as fast due to the influence of gravity.

2. Does the strength of gravity affect the muzzle velocity of a gun?

Yes, the strength of gravity does affect the muzzle velocity of a gun. The force of gravity is directly proportional to the mass of the object and inversely proportional to the distance between the object and the center of the Earth. So, if the strength of gravity is stronger, the bullet will experience a greater downward force and will have a lower muzzle velocity.

3. How does the angle of firing affect the effect of gravity on muzzle velocity?

The angle of firing can have a significant impact on the effect of gravity on muzzle velocity. When a gun is fired at an angle, the force of gravity acts on the bullet in both the vertical and horizontal directions. This results in the bullet traveling a longer distance but with a lower velocity compared to when it is fired straight up. The optimal angle for maximum muzzle velocity is 45 degrees.

4. Can the effect of gravity on muzzle velocity be decreased?

Yes, the effect of gravity on muzzle velocity can be decreased by increasing the initial velocity of the bullet. By increasing the initial velocity, the bullet will have more kinetic energy, which can counteract the downward force of gravity and maintain a higher muzzle velocity over a longer distance.

5. How can the effect of gravity on muzzle velocity be calculated?

The effect of gravity on muzzle velocity can be calculated using the formula: V = √(Vo² - 2gd), where V is the muzzle velocity, Vo is the initial velocity, g is the acceleration due to gravity (9.8 m/s²), and d is the distance traveled. This formula takes into account the decrease in potential energy due to the influence of gravity on the bullet.

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