I believe the answer may be C.) Joules
The time it takes for a point to reach 0 displacement from maximum displacement is
of a cycle. Thus, one period (
) will take
.
The frequency is simply
.
The speed is given by:
The correct answer is D. Atoms of the same element can have different number of neutrons.
You could talk about how the planets spin around the sun, how the universe has galaxies, and we are in the milky way. Blue shift and red shift,etc?