Answer:
dV/dt = 155.74 ft^3/minute
Step-by-step explanation:
Volume V = Area × thickness
Area A= πr ^2
Thickness = 0.2 ft
Volume V = 0.2A = 0.2πr^2
V = 0.2πr^2
Differentiating both sides;
dV/dt = 0.2π × 2r dr/dt = 0.4πr.dr/dt
Given;
r = 400 ft
dr/dt = 0.31 ft/minute
π = 3.14
Substituting the values
dV/dt = 0.4πr.dr/dt = 0.4 × 3.14 × 400 × 0.31
dV/dt = 155.74 ft^3/minute
Answer:
<em>11.29 grams </em><em>of strontium-90 were present in the original rock sample in 1933.</em>
Step-by-step explanation:
Strontium has a half-life of 28.8 years. Therefore,
1989 - 1933 = 56 years.
56 / 28.8 = 1.94 half-lives
Thus, the quantity of the radioisotope remaining will double for each half-life elapsed. moving backwards in time.
Therefore, moving backwards in time by 1.94 half-lives, the quantity remaining will double by 1.94 times.
Thus, the amount remaining in 1933 is
3.0 × (1.94)² = <em>11.29 grams</em>
Answer:
b) 2.7632
Step-by-step explanation:
To find the mean, we multiply each value by it's probability. So
So the correct answer is:
b) 2.7632
273.32 is the surface area. Hope this helps!
Answer:
Step-by-step explanation:
Let x = number of books that Hannah donated
We know that the number of students is 150 and the total number of books is represented by b, we can write that as:
Average number of books donated by each student = 
Now we know that Hannah donated 3 times as much as the average. We can write that as:
