Question

marble place the red circle on the answer. students performed several trials using the laboratory setup shown. students were also given this hypothesis: if friction increases, then the rolling distance of a marble will decrease. what should be changed to best test this hypothesis? a. height of the ramp b. height and length of the ramp c. roughness of the ramp surface d. height of the ramp and roughness of the ramp surface

Explanation:

To test the hypothesis about friction and rolling distance, the independent variable should be friction. Friction depends on the roughness of the surface. Changing the roughness of the ramp surface (option C) directly manipulates friction. Changing ramp height (A, B, D) affects the marble's initial potential energy and speed, not friction directly. So C is the correct choice to isolate the effect of friction on rolling distance.

Answer:

C. Roughness of the ramp surface