It is stable if the atom has a full outer shell
Light waves are never 'aborted'.
They can be 'absorbed', and I think that's what you mean.
It's what happens when light hits something or goes into it,
and never comes out.
"Absorb" just means "soak up". When a light wave hits something and
gets soaked up in it, it's gone, and never comes out the other side.
The light wave certainly gets changed ... it no longer exists.
The object that absorbs it also gets changed. It soaks up the energy
in the light wave, and it has a little more internal energy (heat) than it
had before the light hit it.
Answer:
The time-interval of the collision is 
Explanation:
As given the force is equal to the rate of change of momentum. Mathemticaly this is:
We can rearrange this equation to solve for 
which gives
which is our answer.
In words this means the time interval is equal to the momentum change in that interval divided by the force applied that caused this momentum change.
Since it is a smooth marble and basing from the graph, it has a constant slope, you could just get any two points along the line and get its slope since speed is Δd/Δt. Let the points be (4,6) and (6,9). Thus,
Δd/Δt = (9-6)/(6-4) = 1.5
Thus, the average speed is 1.5 m/s.
