The correct option is **(d) mv**

Momentum = Mass x Velocity

Momentum is the quantity of motion and is compounded by the quantity of the matter moved and the velocity with which it moves. The object tends to be in motion and therefore is a vector quantity. It is determined by the product of the mass of the object and its velocity. If both the objects are not experiencing any external forces, then the total momentum of the objects before and after the interaction is the same.

### Conservation of momentum

Conservation of momentum, the general law of physics according to which the quantity called momentum that characterizes motion never changes in an isolated collection of objects; that is, the total momentum of a system remains constant. We use conservation of momentum to find the change in momentum, and using the impulse-momentum equation, we find the force that the block applies to the bullet.

Some examples of the law of conversation of momentum:

- Air-filled balloons
- System of gun
- bullet Motion of rockets