Of the following, which is directly related to an object's mass and velocity?

Time is a measure of duration and is not directly related to mass or velocity. While time can influence motion (e.g., in calculating distance or speed over time), it does not inherently depend on the mass of an object or its velocity. Thus, time is an independent variable that does not contribute to the concept of momentum.

Density is defined as mass per unit volume, which means it relates to mass but not directly to velocity. While an object's mass contributes to its density, the velocity of an object does not play a role in determining its density. Therefore, density cannot be used to describe the relationship between mass and velocity in the context of momentum.

Displacement refers to the change in position of an object and is a vector quantity that accounts for distance and direction. Although displacement can be influenced by an object's velocity over time, it does not have a direct relationship with mass. As such, displacement is unrelated to the mass-velocity relationship that defines momentum.