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When a bulltet is fired from a rifle it is the bullet which causes damage but nit recoiling gun answer you according to momentum or third law of motion?
Wiki User
∙ 10y ago
I believe that you are asking if the bullet is what causes so much damage to something it strikes, then why doesn't the shooter suffer an equivalent amount of damage? The answer does have a lot to do with momentum. I think that there may be some confusion between the conservation of momentum, which is the essence of Newton's Third Law, and the definition of kinetic energy.
The magnitude of the momentum of the bullet just as it leaves the barrel of a gun is equal to, but in the opposite direction of, the magnitude of the momentum of the gun plus any momentum imparted to the shooter's body.
I apologize if you already know much of my answer, but I will show the equations for momentum and kinetic energy. Momentum is a vector because it has both direction and magnitude, and the equation for momentum is p = m•v, where p is momentum, m is the object's mass in kg, and v is the object's velocity in meters/sec. (The vector quantities are in bold. I'm using the units prescribed in the kms system.)
The reason the bullet causes damage to whatever it strikes is due to the bullet's kinetic energy, which is defined by the equation Ek=1/2mv2, where m is the mass of the bullet in kg and v is the bullet's speed in meters/sec. The fact that the kinetic energy is proportional to the square of the velocity is of paramount importance. Just like momentum, energy is also conserved. Energy (or the combination of energy and mass in the cases of nuclear fission and nuclear fission) is never lost; it can only change forms. All the energy released from every bullet, bomb, and shell used in World War II, or any other war, is still present somewhere in the universe, although almost all of it is still present on the Earth in some form. Thus, the kinetic energy of a bullet fired from a gun is initially exactly equal to the kinetic energy imparted to the backward-moving gun, the gun's report, the flash of light from the muzzle, the heating of the gun's receiver, chamber, and barrel, the heating of the bullet and of whatever it hit, the frictional heating of the air through which the bullet passed, and the energy expended in damaging what the bullet struck.
The reason the shooter of the gun is not severely damaged (although anyone who has ever fired a very powerful rifle such as a 375 H&H or a 460 Wetherby Magnum might disagree) is because the energy of the bullet is proportional to the square of the velocity. Because the mass of the gun is so much greater than the mass of the bullet, the rearward velocity of the gun is very much less than the velocity of the bullet such that the gun cannot cause significant damage to the shooter.
Wiki User
∙ 10y ago
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When a 3.8 kg rifle fires a 13 gram bullet it experiences a recoil velocity of 2.4ms-1Calculate the velocity of the bullet?
Before the shot, total momentum of the rifle/bullet system is zero. Momentum is conserved, so must total zero after the shot. Magnitude of momentum = m V (mass, speed); we'll take care of direction independently. Momentum of the rifle: m V = (3.8) x (2.4) = 9.12 kg-m/sec backwards. We need momentum of the bullet = 9.12 kg-m/sec forward m V = 9.12 ===> V = ( 9.12 / m ) = ( 9.12 / 0.013 ) = 701.54 m/s forward
A bullet of mass 10 grams moving with a velocity of 400 m s gets embedded in a freely suspended wooden block of mass 900 grams what is the velocity acquired by the block?
The answer is: The momentum (mv) after the collision is the same asthe momentum before it. The rest is just arithmetic.Before the collision, the momentum of the bullet is mv=(0.01)x(400) = 4 kg-m/sec.After the collision, the combined mass of the wood block plus the bullet is 910 gm.Its momentum mv=(0.910)x(v) = 4 kgm-m/sec.v = 4/0.910 = 4.396 m/sec .I've ignored the momentum lost during the embedding due to crunching and splintering,both because I don't know anything about the properties of the wood, and also becauseI wouldn't know what to do with them.
If you fired a gun in space would you accelerate in the opposite direction at the same speed as the bullet?
No. Assuming you have a gun that can fire in space, you would travel in the opposite direction, conserving momentum, but because you are more massive than the bullet, your speed in the opposite direction would be less. Momentum is mass*velocity, so your speed should be less than the bullet's by the same factor as the ratio of the bullet's mass to your own. You would also start rotating unless your shot was perfectly aligned with your center of mass.If that's not convincing, consider what happens if you shoot a bullet straight into the air. Does the earth move in the opposite direction at the same speed?
A rifle of mass 2 kg is suspended by strings the rifle fires a bullet of mass 0.01 kg at a speed of 200 ms the recoil velocity of the rifle is what?
I think this would be a problem of momentum. p=mv so if the momentum of the bullet is 20 (.01x200=20) then the recoil velocity should equal 10 m/sec (2x10=20). Good old Newtons 3rd Law.
A bullet with a mass of 0050kg is fired from a gun of a mass 9kg the bullet has a velocity of 250ms What is the velocity with which the gun recoils?
the conversion of momentum law states that the total momentum of twos systems must be equal therefore M1V1 = M2V2 i am assuming the mass of the bullet is 0.0050 kg and not 50kg so (0.0050 * 250) = ( 9 * X) X = (1.25 / 9) X = 0.139 You can't answer these kind of questions with so few parameters. The bullet diameter, barrel length, powder burn rate all greatly effect the answer. The recoil is caused mainly by the gas exiting the barrel, hence muzzle brakes work.
Why does a gunner feel a backward jerk when firing a gun?
This is conservation of momentum. You have the hot gases from the explosive charge along with the bullet moving out the barrel, away from the person. Momentum is mass times velocity. While the mass of the bullet and gases are small, the velocity is very high. So nothing was moving before the trigger was pulled, so net momentum is zero. After the trigger is pulled, the momentum is still net zero. Any momentum away from the gunner will have an equal momentum (the gun recoiling) toward him. Since the gun has much more mass than the bullet, the velocity is much less.
How does a bullet fired from a gun have ahigh momentum?
Momentum = mass x velocity A bullet has a high momentum because its velocity is really high.
Which has more momentum a gun or the bullet it fires?
If the gun is stationary before the shot, then the momentum of the gun and the momentum of the bullet are equal and opposite after the shot.
Why is the momentum of a bullet equal to that of a gun?
In the recoil? This follows from conservation of momentum. Actually, the momentum of the gun will be exactly opposite - or the negative - of the bullet's momentum. It can also be derived from Newton's Second and Third Laws.
What is the recoil velocity of the pistol when a bullet of mass 20g is fired with a velocity 150ms from a pistol of mass 2kg?
Momentum before = momentum after. Since there was no movement before, momentum before = 0 If you think of the bullet as forward/positive momentum and the gun as backward/negative momentum then the momentum of the bullet plus the momentum of the gun =0 and therefore the momentum of the bullet = the momentum if the gun. momentum = mass x velocity P=m/v 20gx150m/s = 2000g (2kg) x velocity 3000 = 2000v 3000 / 2000 = v v = 1.5m/s
What is and example of conservation of momentum?
In an isolated system the total momentum of a system remains conserved. For example If you fire a bullet from Gun , bullet go forward with some linear momentum and in order to conserve the linear momentum the gun recoils
Which has more momentum a train at rest or a bullet fired from a gun?
A bullet fired from a gun
What has more momentum an elephant walking or a bullet?
The elephant
When a gun is firesit recoils why?
Because linear momentum is conserved. Before the shot, the momentum of (gun + bullet) is zero, so it has to be zero after the shot. The bullet gains forward momentum when fired, so the gun must gain reverse momentum in order to maintain the zero sum.
Why does a slow-moving loaded truck and a speeding rifle bullet each have a large momentum?
Momentum is the product of velocity and mass.
What is the momentum of a bullet fired from a gun?
It is known as the Velocity (speed).
A 5g bullet is fired from a 500g if the bullet leaves the gun going 800ms with what speed does it recoil?
The idea is to use conservation of momentum. The momentum before the shot is fired is assumed to be zero, so write an equation that states that the momentum after the shot is zero, and solve it. The total momentum, of course, is the sum of the momentum of the two parts; for each part, the momentum is mass x velocity.
