What exactly makes an object move? Momentum is $\vec p= mv$ where $m$ is mass of an object and $v$ is the velocity of an object, and as a result of this when I fire a bullet the bullet may travel much faster but the gun will recoil or move in opposite direction with the same momentum.
This seems well and good and we can say momentum makes objects move, but since kinetic energy is $\frac{1}{2}mv^2$ where $m$ is mass of an object and $v$ is the velocity of an object. That let us assume the mass of the bullet is $10$kg (very large bullet!) and is accelerated or is velocity is $1000$ $m/s$ which should mean that the kinetic energy is $5,000,000$ joules of Kinetic Energy and momentum is $10000$ $kg$ $m/s$. That said let us assume the mass of the gun is $100$ $kg$ then for the momentum to be conserved here then the velocity of the gun that would recoil backwards would be $100$ $m/s$ so its kinetic energy is $500,000$ joules which is 10 times less than the bullet.
I'm confused here, because of newtons 3rd law - "Every action has an equal and opposite reaction" so I think momentum moves an object but however kinetic energy is the energy of the movement so shouldn't both (gun & bullet) have equal kinetic energies?
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