Answer:

Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:

where these are the masses are initial velocities of both players.
After the collision we have:

since they clong together, acting as one body.
This means we have:

Or:

Which for our values is:

Answer:
a car
A sled sliding across snow or ice.
a ball down a hill
mercury
Explanation:
I think it’s maybe 2. But I’m not sure
-- There is nothing on the list of choices that you provided that has no mass.
-- There are no "things" that have no mass. Every sample of a liquid, a gas,
or a solid has mass, even if it's only an atom or two.
I think the only possible items you could name that have no mass would be
spiritual, conceptual, or sensory ones, like maybe ...
-- idea
-- conviction
-- belief
-- concept
-- image
-- sound
-- illusion
-- impression
-- agreement
-- inclination
-- tendency
-- sparkle
-- tingle
-- pain
Things like that.