Explanation:

Momentum is defined as the product of mass and velocity. A train at rest has a mass but no velocity, so its momentum is zero. A bullet fired from a gun has both mass and velocity, so its momentum is greater than zero.

Momentum is a vector quantity, which means it has both magnitude and direction. The magnitude of momentum is the product of mass and speed, while the direction of momentum is the same as the direction of velocity.

In the case of the train at rest, the magnitude of momentum is zero because the velocity is zero. In the case of the bullet fired from the gun, the magnitude of momentum is greater than zero because the velocity is greater than zero.

Therefore, the bullet fired from the gun has more momentum than the train at rest.