The forces are gravity (weighing down) and internal gas pressure (pushing away from the surface).
Explanation:
option D
you compare the data from your experimental results to the prediction being tested
Answer:
a. Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.
Explanation:
Light pollution is due to the excessive and misdirected use of artificial light. Light bulbs are often design in an incorrect way, since a great part of its light is not completely directed to the ground and an important percentage is emitted to the sky in where will be scattered and reflected back to ground by the particles in the atmosphere. That brings as an effect a sky glow, therefore the visibility of astronomical objects will be extremely reduce.
Hence, professional astronomical research and amateur observations will be affected. Light pollution has a negative impact on bird migration at night and in the health of difference species, humans also.
Answer: 3.1107grams of fat.
Explanation:The speed to cover 800 km in 20 hours will be 40km/hr, Because
Speed =Distance/Time.
This is equal to 72,000 seconds. At a power consumption of 1.7 W, the bird will consume (1.7 X 72,000) =122,400 J of energy.
A gram of fat contains about (9.4 Calories X 4186 J/Calorie) ,=39348 joules of energy, the bird will need (122,400 / 39,348) = 3.1107 grams of fat.
Answer:

Explanation:
Index of refraction:
where
is the refractive index,
is the speed of light in vacuum and
is the speed of light in medium.
The speed of light in vacuum is 
Speed of light in medium is 
Thus,

Index of refraction of this substance through yellow light is 