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oneamp
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If F=ma, why does a bullet that's going a constant velocity, have enough force to penetrate an object?
Why Does a Bullet Penetrate an Object? | Exploring F=ma
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In summary, a bullet has enough force to penetrate an object due to the deceleration it undergoes when it hits something.
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Dale
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It doesn't go at a constant velocity. A bullet decelerates very rapidly.
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Doc Al
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A moving bullet doesn't have 'force', it has momentum and energy. Under the right conditions, that energy may be sufficient to allow the bullet to penetrate an object. During the collision, forces are generated that slow down and deform the bullet.oneamp said:
[STRIKE]And as DaleSpam stated, [/STRIKE]a bullet doesn't move with constant velocity. The air exerts a retarding force on it.
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oneamp
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Thanks...
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russ_watters
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I'm pretty sure that's not what he meant. I'm pretty sure that he meant that in the case being described by the OP - when the bullet hits something - it isn't going at a constant velocity, it is decelerating very rapidly, which involves a very large force.Doc Al said:
...We've gotten almost this exact question several times in the past few days...
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LikesIntuition
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You could look at the bullet's behavior in a vacuum, in which case there would be no air friction. Then it would travel at a constant velocity, and when it hit something, some sort of impulse would occur, which involves forces over some period of time that change the momentum of both the bullet and whatever it's hitting, but conserve the total momentum.
This is exactly what's happening in the air, too. It's traveling through a "vacuum" of space, that also happens to be filled with air molecules. So when the bullet runs into those molecules, the interaction I described above happens. Sorry if that just sounds like rambling, but I figured another take on it might help you glean some more insight!
And if your question is specifically about how a thing moving at a constant velocity can deliver a force, then it's like the posters above were saying: when the bullet makes contact with anything else, it does accelerate (changes velocity) and that acceleration is the one in the F=ma equation, not its lack of acceleration BEFORE the impact. The bullet has no "force" if it isn't interacting with something. Hope that helps a bit!
This is exactly what's happening in the air, too. It's traveling through a "vacuum" of space, that also happens to be filled with air molecules. So when the bullet runs into those molecules, the interaction I described above happens. Sorry if that just sounds like rambling, but I figured another take on it might help you glean some more insight!
And if your question is specifically about how a thing moving at a constant velocity can deliver a force, then it's like the posters above were saying: when the bullet makes contact with anything else, it does accelerate (changes velocity) and that acceleration is the one in the F=ma equation, not its lack of acceleration BEFORE the impact. The bullet has no "force" if it isn't interacting with something. Hope that helps a bit!
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Doc Al
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Ah, OK. I was wondering, since I would not have said that a bullet decellerates rapidly through the air.russ_watters said:
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GANESH PRASAD
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penetration of bullet
It penetrates not due to its velocity but by the deceleration provided by the body into which it penetrates. hence by action reaction force is exerted and the bullet penetrates
hope this helps.
if there is need of further comprehension please feel free to reply.
regards
GANESH PRASAD
oneamp said:
It penetrates not due to its velocity but by the deceleration provided by the body into which it penetrates. hence by action reaction force is exerted and the bullet penetrates
hope this helps.
if there is need of further comprehension please feel free to reply.
regards
GANESH PRASAD
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adjacent
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Mathematically,
##F=\frac{mv-mu}{t}##
For example,if a bullet(0.2kg) had an initial velocity of 500m/s and it stopped after 0.5 sec,then:
##F=\frac{0.2*0-0.2*500}{0.5}=-200N##
So the wall applied 200N on the bullet and the bullet also applied 200N.
minus sign (-) indicates the force is opposite to the direction of motion.
##F=\frac{mv-mu}{t}##
For example,if a bullet(0.2kg) had an initial velocity of 500m/s and it stopped after 0.5 sec,then:
##F=\frac{0.2*0-0.2*500}{0.5}=-200N##
So the wall applied 200N on the bullet and the bullet also applied 200N.
minus sign (-) indicates the force is opposite to the direction of motion.
FAQ: Why Does a Bullet Penetrate an Object? | Exploring F=ma
What is the basic concept behind a bullet penetrating an object?
The basic concept behind a bullet penetrating an object is the application of Newton's Second Law of Motion, which states that the force (F) acting on an object is equal to the mass (m) of the object multiplied by its acceleration (a). In simple terms, the greater the force and acceleration of the bullet, the more likely it is to penetrate an object.
How does the force of a bullet compare to the force of an object it is penetrating?
The force of a bullet is significantly greater than the force of the object it is penetrating. This is due to the high velocity and small surface area of the bullet, which concentrate the force on a smaller area, causing it to penetrate the object.
What factors affect the penetration of a bullet into an object?
Several factors can affect the penetration of a bullet into an object, including the velocity of the bullet, the mass and shape of the bullet, the density and thickness of the object, and the angle at which the bullet strikes the object. Additionally, factors such as bullet material and design can also play a role in penetration.
Why do softer materials, such as water or flesh, allow a bullet to penetrate more easily?
Softer materials allow a bullet to penetrate more easily because they are more compressible and do not offer as much resistance to the force of the bullet. This means that the bullet can more easily transfer its force to these materials, causing them to deform and allowing the bullet to continue traveling through the object.
Can a bullet penetrate an object without breaking the speed of sound?
Yes, a bullet can penetrate an object without breaking the speed of sound. The speed of sound is only relevant when considering the shockwave effects of a bullet, which can cause additional damage. However, a bullet can still penetrate an object at slower speeds due to its high force and small surface area, as explained by Newton's Second Law of Motion.