I'm pretty sure it is true. (78% sure)
Answer:

Explanation:
Refractive Index: It is a measure to find how fast the light travels through a medium. It is ration of the speed of light in vacuum to speed of light in the medium. Speed of light is not constant and varies depending on the density of the medium.
In vacuum the speed of light is 300000 km/s and is denoted by c. When the light beam enters any medium the speed will decrease. Here it is given that the speed in plastic is v. Thus the refractive index(n) is given as:

It is a dimensionless no.
Answer:
original mass of the block of ice is 38.34 gram
Explanation:
Given data
cup mass = 150 g
ice temperature = 0°C
water mass = 210 g
water temperature = 12°C
ice melt = 2 gram
to find out
solution
we know here
specific heat of aluminum is c = 0.900 joule/gram °C
Specific heat of water C = 4.186 joule/gram °C
so here temperature difference is dt = 12- 0 = 12°C
so here heat lost by water and cup are given by
heat lost = cup mass × c × dt + water mass × C × dt
heat lost = 150 × 0.900 × 12 + 210 × 4.186 × 12
heat lost = 12168.72 J
so
mass of ice melt here = heat lost / latent heat of fusion
here we know latent heat of fusion = 334.88 joule/gram
so
mass of ice melt = 12168.72 / 334.88
mass of ice melt is 36.337554 gram
so mass of ice is here = mass of ice melt + ice melt
mass of ice = 36.337554 + 2
mass of ice = 38.337554 gram
so original mass of the block of ice is 38.34 gram
I believe that the answer is A but correct me if i’m wrong
Answer:
A. The upward pressure gradient force is balanced by gravity.
Explanation:
A. is correct because the pressure difference is actually generated by gravity. As in the following formula for the pressure at different points:

where
are the pressure at 2 points, ρ is the density of the fluid, g is the gravitational constant, and h is the height difference.
B is incorrect because friction in air is too small to make an effect.
C is incorrect because the Coriolis force is horizontal, not vertical.
D is incorrect because a difference of 500 hPa = 50000 Pa, this is half of the atmospheric pressure.
E is incorrect because temperature cannot generate force.