v = x/t
v = average velocity, x = displacement, t = elapsed time
Given values:
x = 6km south, t = 60min
Plug in and solve for v:
v = 6/60
v = 0.1km/min south
The description of the question provided above points out to the famous Big Bang Theory. In addition, this theory is among the most accepted by cosmologists because it fits like a glove to the phenomenon the universe is experiencing right now: it is expanding and distances between celestial bodies are getting farther and farther.
The answer is a property of density. The higher the density, the higher the pressure at the bottom.
Pressure = mass / Area. So given that the 4 samples occupy the same area at the bottom, the mass is going to be the determining factor. Per given volume, mercury has the largest mass. The answer is A