Here's why:

* Momentum is a measure of how much motion an object has. It's calculated by multiplying an object's mass (m) by its velocity (v):

* Momentum (p) = mass (m) x velocity (v)

* Direct Proportionality: If you increase the velocity of an object, you increase its momentum. The two quantities change in the same direction.

Example:

Imagine a car with a certain mass. If you double its velocity, you double its momentum.

Inverse Proportionality: Inverse proportionality means that if one quantity increases, the other decreases. This is not the case with momentum and velocity.