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Answer:
Amount of Niobium-91 initially
= 300/91 =3.2967mol
2040 years = 3 ×680 = 3 half-lives
therefore, amount left = 0.4121mol
mass of Niobium-91 remaining = 0.4121 ×91 =37.5g
Please give brainliest
A. The point estimate of μ1 − μ2 is calculated using the value of x1 - x2, therefore:
μ1 − μ2 = x1 – x2 =
7.82 – 5.99
μ1 − μ2 = 1.83
B. The formula for
confidence interval is given as:
Confidence interval
= (x1 –x2) ± z σ
where z is a value
taken from the standard distribution tables at 99% confidence interval, z =
2.58
and σ is calculated
using the formula:
σ = sqrt [(σ1^2 /
n1) + (σ2^2 / n2)]
σ = sqrt [(2.35^2 /
18) + (3.17^2 / 15)]
σ = 0.988297
Going back to the
confidence interval:
Confidence interval
= 1.83 ± (2.58) (0.988297)
Confidence interval
= 1.83 ± 2.55
Confidence interval
= -0.72, 4.38
<h2>A = 0.625</h2>
There are 8 points between 1 and 0 so divide 1 by 8.
1 / 8 = 0.125
Each point has a value of 0.125.
You can minus 0.125 from 1 until you reach A.
Or you can multiple 0.125 by the number of points from 0 to A, including A.
1 - 0.125 - 0.125 - 0.125 = 0.625
0.125 * 5 = 0.625
<h2>A = 0.625</h2>
After 1.4 seconds, t = 1.4.
h(t) = 150 - 9(1.4)
Multiply 9 by 1.4 to get 12.6.
h(t) = 150 - 12.6
Subtract 12.6 from 150 to get 137.4.
h(t) = 137.4.
The height of the ball would be 137.4 after 1.4 seconds.
Hope this helps!
