Answer:
the correct one is D
Explanation:
A question that can be answered with a scientific investigation must be a question where measurements of some kind can be made and with these measurements check that the question is correct or not.
When examining the answers the correct one is D
Answer:
210 m
Explanation:
Given:
a = -6.8 m/s²
v₀ = 54 m/s
v = 0 m/s
Find: Δx
v² = v₀² + 2aΔx
(0 m/s)² = (54 m/s)² + 2 (-6.8 m/s²) Δx
Δx ≈ 210 m
Answer:

Explanation:
Refraction: It is a process in which light ray travel from one medium to another medium.
When a light travel form one medium to another medium then the speed of light changes.
When a light travel from rare to denser medium then the light bend towards normal .
When a light travel form denser to rare medium then the light ray bend away from the normal.
Refractive index:It is a ratio of velocity of light in vacuum to the velocity of light in medium .It is a measure of change in speed of light when it passes from vacuum into material.It is represented by "n''.
Mathematical representation:

Where n=Refractive index of material
c=Velocity of light in vacuum
v=Velocity of light in medium