Here's why:

* Mass: The more massive an object is, the more kinetic energy it has at a given velocity. This is because it takes more energy to get a heavier object moving.

* Velocity: The faster an object is moving, the more kinetic energy it has. This is because the energy is proportional to the square of the velocity.

The mathematical formula for kinetic energy is:

KE = (1/2) * m * v^2

Where:

* KE = kinetic energy

* m = mass

* v = velocity