The answer is C, because they moved from a stand still to down the hill
In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture.
T = 2 * pie √(L/g)
so, if length is increased by 9
then time period is increased by √9 = 3
hope it helped :)
Answer:
C
Explanation:
light can travel in a vacuum Anne the sped varies