Momentum, defined as the product of mass and velocity, is a vector quantity, while mass is a scalar. Both momentum and velocity share similarities, such as being collinear vectors that have the same unit vector. The magnitude of momentum increases when mass is greater than one, but this is dependent on the choice of units, making comparisons arbitrary. Additionally, force represents the change in momentum when mass is constant, linking acceleration and momentum through their definitions. Overall, the discussion highlights the complexities and arbitrary nature of comparing magnitudes of momentum and velocity.