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Ann [662]
3 years ago
5

Sodium-24 has a half-life of 15 hours. how many grams of a 900 g sample will remain after 90 hours

Mathematics
1 answer:
raketka [301]3 years ago
4 0

Answer: Option 'B' is correct.

Step-by-step explanation:

Let the initial concentration be

N_0=900\ g

Let concentration after t= 90 hours be N

Since we have given that Sodium-24 has a half life of 15 hours i.e.

t_{\frac{1}{2}}=15

So, According to question,

\text{ Number of half lives }=\frac{t}{t_{\frac{1}{2}}}\\\\\text{ Number of half lives }=\frac{90}{15}\\\\\text{ Number of half lives }=6

As we know that

\frac{N}{N_0}=(\frac{1}{2})^n\\\\N=N_0\times (\frac{1}{2})^n\\\\N=900\times (\frac{1}{2})^6\\\\N=\frac{900}{64}\\\\N=14.0625\ g

Hence, Option 'B' is correct.

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Volume = length * width * depth
width = Volume / (length * depth)
width =  7.35 / (4.2 * .5)
width =  3.5 meters

Double Check
Volume = 4.2 *.5 *3.5 = <span> <span> <span> 7.35 </span> </span> </span> cubic meters correct !!



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3 years ago
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nlexa [21]

Answer:

Go to brainfuse.com

Step-by-step explanation:

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3 years ago
What graph represents the inequality y&lt;2x-1
Black_prince [1.1K]

Answer:

See attached.

Step-by-step explanation:

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2 years ago
Just this please helppp
Murrr4er [49]

The height of the <em>water</em> depth is h = 14 + 6 · sin (π · t/6 + π/2), where t is in hours, and the height of the Ferris wheel is h = 21 + 19 · sin (π · t/20 - π/2), where t is in seconds. Please see the image to see the figures.

<h3>How to derive equations for periodical changes in time</h3>

According to the two cases described in the statement, we have clear example of <em>sinusoidal</em> model for the height as a function of time. In this case, we can make use of the following equation:

h = a + A · sin (2π · t/T + B)     (1)

Where:

  • a - Initial position, in meters.
  • A - Amplitude, in meters.
  • t - Time, in hours or seconds.
  • T - Period, in hours or seconds.
  • B - Phase, in radians.

Now we proceed to derive the equations for each case:

Water depth (u = 20 m, l = 8 m, a = 14 m, T = 12 h):

A = (20 m - 8 m)/2

A = 6 m

a = 14 m

Phase

20 = 14 + 6 · sin B

6 = 6 · sin B

sin B = 1

B = π/2

h = 14 + 6 · sin (π · t/6 + π/2), where t is in hours.

Ferris wheel (u = 40 m, l = 2 m, a = 21 m, T = 40 s):

A = (40 m - 2 m)/2

A = 19 m

a = 21 m

Phase

2 = 21 + 19 · sin B

- 19 = 19 · sin B

sin B = - 1

B = - π/2

h = 21 + 19 · sin (π · t/20 - π/2), where t is in seconds.

Lastly, we proceed to graph each case in the figures attached below.

To learn more on sinusoidal models: brainly.com/question/12060967

#SPJ1

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1 year ago
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Arisa [49]

Answer:

x is greater than or equal to 3

Step-by-step explanation:

x ≥ 3

x is greater than or equal to 3

so you got the plot right

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