25. Which of the following variables was (were) directly controlled by the experimenter in at least one of the experiments?
I. The amount of mass suspended
II. The period of oscillation
III. The length of wire
IV. The initial displacement angle
Your Answer is
Correct Answer is D
Explanation
The independent variable in Experiment 1 is mass;
The independent variable in Experiment 2 is length;
The independent variable in Experiment 3 is angle.
So there are I, III, and IV