Set this up as
10 = 40 (1/2)t/28
and solve for t in years.
10/40 = (1/2)t/28
log(0.25) = (t/28) log(0.5)
t = 28 log(0.25) / log(0.5) years = 56 years
Test the answer:
56 years = 2(28 years) = 2 half-lives, so the remaining amount should be 1/2 of 1/2 of the initial amount, i.e. 1/4 of the initial amount, and 10 mg = 1/4 of 40 mg.
Answer:
C. Principle of original horizontality
Explanation:
The Law of Original Horizontality suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed. This allows us to infer that something must have happened to the rocks to make them tilted.
At low latitudes, the thermocline is a zone of rapid temperature
over a relatively short depth. it is associated with a similar depth zone marked by a change in density called the pycnocline.
Answer:
11. On the diagram of the area of sand dune development attached to the answer, draw a sketch showing the general side view of a sand dune formed by a wind blowing in the direction indicated. Your sketch should clearly show any variations in the slope of the sides of the dune.
[1] Allow 1 credit for a correct profile, showing both the windward and leeward sides of the same dune, and showing the steepest gradient on the leeward side. Acceptable responses include, but are not limited to, this example:
12. Allow 1 credit for a correct response. Acceptable responses include, but are not limited to, these examples:
The calcite cement would be chemically weathered and removed by infiltrating water.
It would be dissolved.
It will bubble.
Answer:
was used to make jewelerly and tableware