Answer:
the spear will end up above the fish relative to the actual position of the fish.
Explanation:
due to refraction of light coming from the fish the fish will appear slightly above from its real position
So due to this refraction the spearfisher will throw the spear directly at the image of the fish due to which it will not reach the position of fish but it will reach the position above the fish.
So here we can say that the spear will end up above the fish relative to the actual position of the fish
Answer:

Explanation:
According to the law of conservation of linear momentum, the total momentum of both pucks won't be changed regardless of their interaction if no external forces are acting on the system.
Being
and
the masses of pucks a and b respectively, the initial momentum of the system is

Since b is initially at rest

After the collision and being
and
the respective velocities, the total momentum is

Both momentums are equal, thus
Solving for 


The initial kinetic energy can be found as (provided puck b is at rest)


The final kinetic energy is


The change of kinetic energy is

A, electrons are negatively charged and do orbit around the nucleons
The answer is the first one