IV - Temperature
DV - Light intensity
Need more details to the question
I would go with A. An Observation. Because he's looking at visual differences, for example: "based on smell, color change, and release of bubbles.
Sounds like you've been given some unnecessary information.
<span>The linear velocity "v" and angular velocity "w" of something in circular motion of radius "R" are related as; </span>
<span>v = Rw </span>
<span>You are given v= 15 m/s and R = 3 m , so just solve for "w".</span>