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Unformatted text preview: 4. Momentum plays a dominate role in modern physics—in relativity and quantum physics—while
the concept of force is secondary in physics of the atom and nucleus. 2. Theory
2.1 Momentum and Impulse
In physics, momentum has a precise definition. A slowly moving elephant has a lot of
momentum, but so does a bullet shot from the muzzle of a gun. We therefore expect that momentum will
depend on an objects mass and velocity.
The linear momentum, p, of an object of mass m moving with velocity v is the product of its
mass and velocity: (1)
SI Unit: kg meter per second (kg m/s)
By looking at equation (1), we can see that doubling either the mass or the velocity doubles it momentum;
doubling both quantities quadruples its momentum. Momentum is a vector quantity with the same
direction as the objects velocity. Its components are given by (2)
where px is the momentum of the object in the x-direction, py its momentum in the y-direction, and pz its
momentum in the z-direction.
Changing the momentum of an object requires the application of a forc...
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