Here's why:

* Momentum (p) is defined as the product of an object's mass (m) and velocity (v):

* p = m * v

* If you double the velocity (v), you are essentially multiplying the original momentum by 2:

* p' = m * (2v) = 2 * (m * v) = 2p

Therefore, doubling the velocity directly results in a doubling of the momentum, assuming the mass remains constant.