So, you have a question: Do objects with different weights fall at different speeds?
And you have a hypothesis: Heavier objects fall faster than lighter objects.
So, of the various things that happen in your experimental design, we call the things that vary, variables. Some variables have their settings decided on by you - these are the independent variables. Some change in response to whatever choices you make for your independent variables. These variables depend on what you set the independent ones at, so they are called dependent variables. I'm guessing that your "controlled" and "manipulated" variables are all independent variables, and your "responding" variable wold be a dependent variable. An interesting choice of terms, but understandable. I will assume that the "controlled" variables are going to be whatever variables you keep constant, because otherwise why have a "manipulated" variable? I will also assume that your "manipulated" variable is whatever one you change. Are you doing multiple repetitions, maybe? Maybe changing the height or the weights? That would make the "responding" variable the one that changes (or not) as you change the "manipulated" variable.