1. is D. Scientific method cannot be replaced.
2. is B.
3. is B as well.
Okay, hun. Velocity is a vector quantity that measures displacement over a period of time. Velocity = Speed/Time (v=s/t). Hope this helped you. I took physics over 4 years ago. I'm more of a biology/chemistry person. (I major in those)
Answer:
857.5 m
2.8583×10⁻⁶ seconds
Explanation:
Time taken by the sound of the thunder to reach the student = 2.5 s
Speed of sound in air is 343 m/s
Speed of light is 3×10⁸ m/s
Distance travelled by the sound = Time taken by the sound × Speed of sound in air
⇒Distance travelled by the sound = 2.5×343 = 857.5 m
⇒Distance travelled by the sound = 857.5 m
Time taken by light = Distance the light travelled / Speed of light

Time taken by light = 2.8583×10⁻⁶ seconds
Hi! The answer is ‘B’! Because the nucleus is found at the center and contains protons (positive charge) and neutrons (no charge)