The momentum goes to the wall
There are several approaches. The most favourable one (in my opinion) is this one:
1. Asking a question
2. Doing a research (how to answer this question)
3. Creating a hypothesis (NOT a thesis!)
4. Experimenting (to prove the hypothesis)
5. Analysing results from the experiment
6. Writing a thesis
Answer:

Explanation:
By energy conservation we know that spring energy is converted into kinetic energy of the block
so we will have

so we will have

now we will have same thing for another mass 4m which moves out with speed 5v
so we have

now from above two equations we have

so we have

No, that's silly.
You've got your Pfund series where electrons fall down to the 5th level,
your Brackett series where they fall to the 4th level, and your Paschen
series where they fall to the 3rd level. All of those transitions ploop out
photons at Infrared wavelengths.
THEN next you get your Balmer series, where the electrons fall in
to the 2nd level. Most of those are at visible wavelengths, but even
a few of the Balmer transitions are in the Ultraviolet.
And then there's the Lyman series, where electrons fall all the way
down to the #1 level. Those are ALL in the ultraviolet.
Well, it goes 60 miles in one hour......so set up a ratio.....
60 miles/5 miles = 1 hr/x.....you'll get 60x = 5....then 5/60 would be 0.083