Momentum:
Momentum is a fundamental concept in physics that describes the motion of an object. It is defined as the product of an object's mass and its velocity. Mathematically, momentum (p) is calculated using the equation:

p = m * v

Where:
p = momentum
m = mass of the object
v = velocity of the object

Components required to calculate momentum:
To calculate the momentum of a body, we need two components:

1. Mass:
Mass is a measure of the amount of matter in an object. It is a scalar quantity and is usually measured in kilograms (kg). The mass of an object determines how difficult it is to change its state of motion, and it is an important factor in calculating momentum.

2. Velocity:
Velocity is a vector quantity that describes the speed and direction of an object's motion. It is the rate at which an object changes its position. Velocity is usually measured in meters per second (m/s). In the context of calculating momentum, we need to consider the velocity of the object.

Explanation of the correct answer:
The correct answer is option 'B' which states that velocity and mass are the components required to calculate the momentum of a body. This is because velocity and mass are the two fundamental quantities that directly affect and determine the momentum of an object.

- Mass is a scalar quantity that represents the amount of matter in an object. It determines the inertia and resistance to changes in motion. The greater the mass, the greater the momentum of the object for a given velocity.
- Velocity, on the other hand, is a vector quantity that describes the speed and direction of an object's motion. It determines how fast an object is moving and in which direction. The velocity of an object affects its momentum, and a greater velocity results in a greater momentum for a given mass.

By multiplying the mass and velocity of an object, we obtain the momentum of the object. Therefore, to calculate the momentum, we need both the mass and velocity of the object.

In conclusion, the correct components required to calculate the momentum of a body are the mass and velocity of the object. These two quantities are necessary to determine the momentum of an object accurately.