By building dams and levees . Hope this helps
Answer:
C. Weight is mass times the acceleration of gravity.
Explanation:
Weight is the force exerted by gravity. Force is equal to mass times acceleration.
Answer:
I believe the answer for #1 is D and the answer for #2 is B
Explanation:
I hope this is correct and helps
Answer:
Let the second medium be air (n₁=1)
The refractive index n₂ of the medium where first medium is air is found (a)
(a) n₂ = 2
Explanation:
Critical angle can be defined as the angle of incidence that provides the angle of refraction of 90°.
Refractive index of a medium can be defined as a number that describes that how fast a light will travel through that medium.
Critical angle and Refractive index are related by:


To find refractive index of medium with respect to air, substitute n₁=1 (Refractive index of air is 1)
Also θ(critical)=30°
Find n₂ :

The change in velocity from 30 m/s north to 40 m/s south is a change of 70 m/s south