Answer:
The initial velocity of the snowball was 22.21 m/s
Step-by-step explanation:
Since the collision is inelastic, only momentum is conserved. And since the snowball and the box move together after the collision, they have the same final velocity.
Let
be the mass of the ball, and
be its initial velocity; let
be the mass of the box, and
be its velocity; let
be the final velocity after the collision, then according to the law of conservation of momentum:
.
From this we solve for
, the initial velocity of the snowball:

now we plug in the numerical values
,
,
, and
to get:


The initial velocity of the snowball is 22.21 m/s.
P.S: we did not take vectors into account because everything is moving in one direction—towards the west.