We know Newton's three laws:
A object at rest will remain at rest, and an object in motion will remain in motion unless a external force acts upon it.
If an unbalanced force acts on a object, the object will accelerate in the direction of the net force.
If an object $A$ exerts a force on object $B$, then object $B$ will exert a equal force to object $A$ in the opposite direction. $F_{a\text{ on }b} = -F_{b\text{ on }a}$
What I think is that as you throw the snow, it begins moving at a constant velocity. However, when the shovel stops moving, the snow will remain in motion, causing it to accelerate/fly toward the snow bank, according to Newton's first law. But is the snow accelerating when it leaves the shovel? How does this apply to Newton's second law? Thanks!