If a gun is fired at the speed of sound, does the projectile travel at twice the speed of sound?

Answer 1

if YOU fire a gun and you are moving at the speed of sound, when you fire the gun you fire it in your direction of travel (ie, forward) AND if the muzzle velocity (speed a bullet leaves the barrel of the gun) of the bullet is equal to the speed of sound then yes, theoretically you would have a bullet moving twice the speed of sound. if you switched it around so that you fired backwards on the path you came from, the bullet would look like it was going the speed of sound to you, but it would actually be sitting still relative to the earth.

Answer 2

Yes, there are some modern sniper rifles that do fire a hyper-sound velocity round. Yes, velocity is a vector and can be added. So, relative to some frame of reference (the earth, the inside of a moving freight train, the inside of a really large spaceship, etc.) if both you and the gun are moving relative to that reference frame and you pull the trigger, the velocity as a vector of the bullet is added to your velocity as a vector.

All the people that are talking about which way the gun is pointing are really referring to the way vectors are added. Imagine them as arrows pointing in the direction of travel and whose length is proportional to how fast it is going. You draw the vector for your velocity and then you start at the tip of the arrow that represents your velocity and you draw another arrow that represents the velocity of the bullet. If they are pointing in the same direction, then the total velocty (the distance from where the first arrow started to the end of the second) is going to be large.

You can play this same game to imagine what will happen if you point the gun to the side and fire or if you point it back the way you came and fire.

Answer 3

If the bullet would travel at the speed of sound if fired from the gun when stationary, and the gun if facing in the same direction as the gun is moving, the bullet would leave the gun at twice the speed of sound. It would begin to slow due to air resistance as soon as it left the gun.

Answer 4

YES it does. But NO that is not why they don't put cannons on supersonic fighters. Why they don't I'm not sure but I would guess it is because they are so fast that they are pretty much worthless for air-ground attack. And also air-air because of missile range.

If you consider that you are in a car traveling at 5 mph and you lean out the window and throw a rock at an elderly person at 5 mph, the velocity of the rock will be the sum of those two speeds. The same applies at any speed. The reason this is, is because while the rock is moving 5 mph in your hand while you are in the car, it's relative speed is 0, just like yours is. Once you increase the relative speed of the rock with your energy it must then be added to the speed of the relative observer. Note: If the relative observer is also traveling at 5 mph, say in a car next to you, then he will record a velocity of only 5 mph for the rock. He will also record a different velocity if he is traveling at any speed in reference to you.

This principle is, however, completely different with light. Einstein is best known for his theories outlining the "speed of light limit". The speed of light never changes, regardless of observer or observed motion.

Answer 5

The simple answer is yes.

As the Physics graduate and mathematics lecturer have adequetly explained. This is of course with assumptions:
1 Gun speed to the fixed frame of refference is the speed of sound.
2 Projectile speed to the gun is the speed of sound.
3 Their verlocity vectors are aligned.

But strictly speaking it would be fractionally less (not even measurable) due to Einstiens relativity equations. Though this is just being a perfectionist.

Answer 6

The speed of sound is not like the speed of light.

If a gun is fired from a aircraft travelling at the speed of sound the velocity of the bullet(which would be in excess of the speed of sound anyway) can be added to the velocity of the aircraft to determine its velocity relative to the ground.

Answer 7

Prometheus is correct.

For example:

If the projectile is loaded to supersonic specifications [let's say a muzzle velocity of Mach 1.001],

And

If the armament is trveling at the speed of sound, Mach 1.000,

And

If the projectile is fired at the exact same vector the armament is travelling,

And

If there is nothing to counteract the muzzle velocity of the projectile once it leaves the muzzle of the armament,

Then

The projectile in question would be travelling at twice the speed of cound, in this example at Mach 2.001.

Answer 8

The bullet slug has a terminal velocity that limits its speed and its not going to travel much faster than the speed of sound. In a vacuum the bullet could travel faster but its not quite the addition of velocity. Even at the speed of sound it is not very noticeable the difference with Einstein's equations, and the addition of velocities. It would be close enough to the real answer to use the addition of velocities but in reality it is slightly less. Planets orbit the sun at much higher velocities and objects slug from them are more noticeable as to Einstein's equations.

Answer 9

Somethings to consider in to the equation, what altitude you are traveling to fire the projectile, plus the speed of the projectile itself, that is determined by the amount of powder,weight of projectile,length of barrel.

Answer 10

Yes, indeed that is correct, but what you should be asking is if you are travelling at the speed of light (which I know is impossible) and you turned on a torch, would the light from the torch be travelling at twice the speed of light?