1. Standard memberAThousandYoung
    Shoot the Squatters?
    tinyurl.com/43m7k8bw
    Joined
    23 Aug '04
    Moves
    26660
    22 Jan '10 04:17
    Originally posted by joe shmo
    It does, when a bullet is fired every thing else in the system moves. Fire a bullet to the right, the universe moves to the left. Its consevation of momentum.
    No, conservation of momentum shows itself in the recoil of the firearm.

    Anyway, momentum and energy are two different things.
  2. R
    Standard memberRemoved
    Joined
    10 Dec '06
    Moves
    8528
    22 Jan '10 04:431 edit
    Originally posted by AThousandYoung
    No, conservation of momentum shows itself in the recoil of the firearm.

    Anyway, momentum and energy are two different things.
    Which in turn,imparts momentum on the person, who imparts momentum on the earth, which changes the momentum of the solar system,galaxy,ect..........Im not wrong.
  3. Standard memberwolfgang59
    Quiz Master
    RHP Arms
    Joined
    09 Jun '07
    Moves
    48793
    23 Jan '10 10:37
    Originally posted by joe shmo
    Which in turn,imparts momentum on the person, who imparts momentum on the earth, which changes the momentum of the solar system,galaxy,ect..........Im not wrong.
    Thats quite correct Joe, I had never considered that the firing of the gun would impart a force (albeit miniscule) on the sun but as you point out it does!

    We always consider Conservation of Momentum within a 'system' but that 'system' (thanks to gravity) is the Universe.

    Or is it? Is there a minimum force (ie a quanta of force)???????????
  4. Standard memberAThousandYoung
    Shoot the Squatters?
    tinyurl.com/43m7k8bw
    Joined
    23 Aug '04
    Moves
    26660
    23 Jan '10 13:33
    Momentum and energy are not the same thing guys...I was talking about energy.
  5. R
    Standard memberRemoved
    Joined
    10 Dec '06
    Moves
    8528
    23 Jan '10 13:36
    Originally posted by wolfgang59
    Thats quite correct Joe, I had never considered that the firing of the gun would impart a force (albeit miniscule) on the sun but as you point out it does!

    We always consider Conservation of Momentum within a 'system' but that 'system' (thanks to gravity) is the Universe.

    Or is it? Is there a minimum force (ie a quanta of force)???????????
    Now this I no almost nothing about, But what about weak nuclear force is that a quanta of force,or is this actually a strong force in comparison to what we are talking about?
  6. R
    Standard memberRemoved
    Joined
    10 Dec '06
    Moves
    8528
    23 Jan '10 13:511 edit
    Originally posted by AThousandYoung
    Momentum and energy are not the same thing guys...I was talking about energy.
    They arent the same, but the are both conservation laws and they are related

    Ke = 1/2*m*v^2 (Kinetic Energy)

    dKe/dv = m*v ( momentum, the rate of change of Kinetic energy with respect to velocity)

    dKe/dt = m*v*dv/dt = m*v*a = P (Power, the rate of change in Kinetic energy with respect to time)
  7. Subscribersonhouse
    Fast and Curious
    slatington, pa, usa
    Joined
    28 Dec '04
    Moves
    53223
    25 Jan '10 16:001 edit
    Originally posted by joe shmo
    They arent the same, but the are both conservation laws and they are related

    Ke = 1/2*m*v^2 (Kinetic Energy)

    dKe/dv = m*v ( momentum, the rate of change of Kinetic energy with respect to velocity)

    dKe/dt = m*v*dv/dt = m*v*a = P (Power, the rate of change in Kinetic energy with respect to time)
    Is there any difference between a Kg of aluminum going 100 Km/hr V a kg of Uranium going 100 Km/hr? It would seem at least the uranium would have more penetrating power as in its use in military ordinance. Is that all there is to it, the mass alone? What about for instance, a billiards ball of standard material V one made of say standard on the outside but lead on the inside, I guess that would be biased because you couldn't make them the same size unless there was a hollow in the lead ball. So what about that, a specialized billiard ball with ordinary stuff on the outer few millimeters and a lead foam inside so they weigh the same, any difference in the kinetics?

    So I googled 'Momentum Vs Kinetic energy' and found this great link with nice thought experiments to explain the difference:

    http://www.batesville.k12.in.us/physics/phynet/mechanics/Energy/KENOTMomentum.html
  8. Standard memberwolfgang59
    Quiz Master
    RHP Arms
    Joined
    09 Jun '07
    Moves
    48793
    25 Jan '10 17:20
    Originally posted by sonhouse
    Is there any difference between a Kg of aluminum going 100 Km/hr V a kg of Uranium going 100 Km/hr? It would seem at least the uranium would have more penetrating power as in its use in military ordinance. Is that all there is to it, the mass alone? What about for instance, a billiards ball of standard material V one made of say standard on the outside but ...[text shortened]... erence:

    http://www.batesville.k12.in.us/physics/phynet/mechanics/Energy/KENOTMomentum.html
    Coefficient of Restitution? (which is probably related to density?)
  9. Standard memberAThousandYoung
    Shoot the Squatters?
    tinyurl.com/43m7k8bw
    Joined
    23 Aug '04
    Moves
    26660
    25 Jan '10 18:06
    Originally posted by sonhouse
    Is there any difference between a Kg of aluminum going 100 Km/hr V a kg of Uranium going 100 Km/hr? It would seem at least the uranium would have more penetrating power as in its use in military ordinance. Is that all there is to it, the mass alone? What about for instance, a billiards ball of standard material V one made of say standard on the outside but ...[text shortened]... erence:

    http://www.batesville.k12.in.us/physics/phynet/mechanics/Energy/KENOTMomentum.html
    They'd have the same energy but the aluminum projectile would be bigger. This means more air resistance, vulnerability to wind, and probably a greater cross section spreading the force over a larger area of armor.

    You're referring to density.

    So what about that, a specialized billiard ball with ordinary stuff on the outer few millimeters and a lead foam inside so they weigh the same, any difference in the kinetics?

    Possibly. It would depend on weight distribution inside the ball and hardness of the ball. Also there's the possibility of deformation; this might be part of "hardness". If those were also the same it should act the same.
Back to Top

Cookies help us deliver our Services. By using our Services or clicking I agree, you agree to our use of cookies. Learn More.I Agree