Describe the momentum concept of Physics in one sentence.
Momentum refers to the product of an object's mass and its velocity and describes the motion of an object and how it is affected by external forces.
Complete the following task based on the instruction and optional input provided.### Instruction:
Describe the momentum concept of Physics in one sentence.

### Output:
Momentum refers to the product of an object's mass and its velocity and describes the motion of an object and how it is affected by external forces.