Pick any free letter for each trait. For example, "A" for the dominant allele and "a" for the recessive allele for the number of arms. Assuming complete dominance, the genotype for the dominant trait will always have at least one "capital" allele, so a creature with 2 arms would have genotype either AA (homzygous dominant) or Aa (heterozygous), while a creature with the recessive trait of having 4 arms will always be homzygous recessive with genotype aa.
Now let’s say you’re on the Moon. If you were to drop a hammer and a feather from the same height, which would hit the ground first?
Trick Question! On the moon both objects would hit the ground at the same time. On Earth, the hammer lands first.
So yeah, the student is right. Galileo gave us this theory long ago.
It would be negative regardless of what you define as a positive direction.
The difference in electric potential energy between the two points is

where q is the magnitude of the charge and

is the electric potential difference.
But for energy conservation, the difference in electric potential energy

between the two points is equal to the work done to move the charge between A and B:

so we have

and by substituting the numbers of the problem, we find the value of

: