A 15-g sample of radioactive iodine decays in such a way that the mass remaining after t days is given by
m(t) = 15e−0.073t,
where
m(t)
is measured in grams. After how many days is there only 5 g remaining?

Answers

Answer 1

15 days

Step-by-step explanation:

The half-life equation is given as

[tex]m(t) = m(0)e^{-0.073t}[/tex] (1)

where m(0) is the initial mass of radioactive iodine at t = 0. To solve for the time t, let's put the exponential part on the left-hand side:

[tex]e^{-0.073t} = \dfrac{m(t)}{m(0)}[/tex]

Taking the natural logarithm of both sides to get

[tex]\ln{e^{-0.073t}} = \ln\left[\dfrac{m(t)}{m(0)}\right][/tex] (2)

Recall the following properties of logarithms:

[tex]\ln{A}^b = b\ln{A}[/tex]

[tex]\ln{e} = 1[/tex]

We can rewrite Eqn(2) as

[tex]-0.073t = \ln\left[\dfrac{m(t)}{m(0)}\right][/tex]

Solving for t, we get

[tex]t = -\dfrac{1}{0.073}\ln\left[\dfrac{m(t)}{m(0)}\right][/tex]

Since m(0) = 15 gm and m(t) = 5 gm, then the amount of time that elapses to reduce the mass down to 5 gm is

[tex]t = -\dfrac{1}{0.073}\ln\left(\dfrac{5\:\text{g}}{15\:\text{g}}\right)[/tex]

[tex]\:\:\:\:\:= 15\:\text{days}[/tex]


Related Questions

someone please answer this I'll mark u as the brainest please anyone it's hard for me. ​

Answers

Answer: D

Step-by-step explanation:

Since it is subtracting x from 20. D tells the change from 20 dollars after buying the notebook or x.

A is 20 + x

B is 20/x

C is 20x or 20 * x

D is 20 - x

Answer:

B

Step-by-step explanation:

you can see the words cut and smaller so that indicates subtraction

Hai has 1 gallon jug of water. He drinks 1/8 gallons of water before lunch and 2/3 gallons of water after lunch. How much water did Hai drink all day?​

Answers

Hai drank 10/16 gallons of water all day

Hai drink 11/24 gallons of water in all day

What is Equation?

Two or more expressions with an Equal sign is called as Equation.

Given,

Hai has 1 gallon jug of water.

Drinks 1/8 gallons of water before lunch

2/3 gallons of water after lunch.

We need to find how much water did Hai drink all day.

Now we have to add the water he drink.

1/8+2/3

LCM of 8 and 3

3+8/24

11/24

Hence, he drink 11/24 gallons of water in all day.

To learn more on Equation:

https://brainly.com/question/10413253

#SPJ2

Solve 4x-4 < 7x - 19

Answers

Answer:

x<5

Step-by-step explanation:

cuz im a methnerd l

Answer:X>5

Step-by-step explanation:

7.
"iş, oluş, durum bildiren köklere fiil kökü denir. Fill
kökleri -mek / -mak mastar eki ile anlamlı şekilde
söylenir."
Açıklamaya göre verilen sözcüklerden hangisi-
nin kökü fiil değildir?
A) evim
B) seçim
C) giyim
D) verim

Answers

Answer:

ABWJRIRISBDBDBHSHS

Step-by-step explanation:

Hatdog HWHWHWHSHSHSQIWIW

AT WHAT X-VALUE DOES A
RELATIVE MINIMUM
OCCUR?

Answers

The graph was too small for me to see so I used the first derivative test to find it:

The answer is 4.24

(Super long explanation, my work is below):

For this test, first you find the derivative of the function, then you set that value to 0 and find the x values. This gives you the critical points, which you can use to test the intervals on the graph. Since this function has an open interval we can use - infinity and infinity as the endpoints of out test. When the value of derivative changes from a negative interval to a positive interval, that is a relative min.

Answer:

  x ≈ 4.239

Step-by-step explanation:

A relative minimum is found at the bottom of any U-shape on the graph. If you expand the graph shown until it has a suitable scale, it can show you the relative minimum occurs at x ≈ 4.239.

__

Additional comment

The relative maximum occurs at the top of any ∩-shape. The graphing calculator can show you that occurs at x ≈ -1.573.

Which is the verbal expression for 11 - 2/n?


Answers

Answer:

(a.)

Step-by-step explanation:

(we talked abt it in the comment haah)

Help ASAP PLEASSEEEEE for 30 points

Answers

First picture:

5). 343

Second Picture:

1). 89

2). -26

3). 20

4). 62

Third Picture:

Equation 1: Associative

Equation 2: Commutative

Equation 3: Associative

Equation 4: Distributive

Equation 5: Commutative

Equation 6: Associative

Last Picture:

1). B).

2). C).

Please mark Brainleist

3
Which number line shows a number equivalent to
1 Sume
Choose 1 answer:
ctions
++
wat tract
>
2
0
1
A
U
HHH
iz 1
X 8 min
>
2
0
1
N
ctions
FE
4HHHH
0
>
2
1
iz 2
6 3 mor

Answers

Answer: B

Step-by-step explanation:

2/3 means 1.5

Savanna have 40 iris blooms last year this year she had 50% more iris blooms how many more iris blooms did savanna have this year

Answers

Answer:

6

Step-by-step explanation:

50% = 0.50
40 x 0.50 = 20
40 + 20 = 60
Savanna has 69 blooms this year.

Kevin buys a bag of cookies that contains 8 chocolate chip cookies, 9 peanut butter cookies, 5 sugar cookies and 4 oatmeal cookies. What is the probability that Kevin randomly selects a chocolate chip cookie from the bag, eats it, then randomly selects an oatmeal cookie

Answers

Answer:

4/13 or 30.769%

Step-by-step explanation:

Find the greatest value of -10+14X-2X^2 and state the value of X at which it occurs

Answers

Answer:

Step-by-step explanation:

a maximum or minimum occurs where the derivative equals zero

f(x) = -2x² + 14x - 10

f'(x) = -4x + 14

0 = -4x + 14

4x = 14

x = 3.5

f(3.5) = -2(3.5)² + 14(3.5) - 10 = 14.5

Use the graph below to answer the question. On a coordinate plane, a line goes through (0, 0) and (3, negative 3). What is the slope of a line that is perpendicular to the line in the graph?

Answers

Answer:

y = x

Step-by-step explanation:

So 1st we need to find the slope of the original line which is y = -x

(use slope formula)

2nd Now we just need to reverse the slope, and that gets us to y = x

Answer: 6

its obvious  

Musa had 3/ 5 ton of grain for all the animals on his large farm. He used 1 /20 ton each day to feed all his animals. How many days was it until Musa needed more grain?

Answers

Answer:

12 days

Step-by-step explanation:

'd' = number of days

1/20d ≤ 3/5

multiply each side by 20 to get:

d ≤ 60/5 or d ≤ 12

Un estudiante de Astronomía sabe que Venus le da la vuelta al Sol 225 días y Marte 687 días . Si sabe que la última vez que v s , tierra y Marte se alinearon fue hace 1805645 días , ¿ en cuanto tiempo se volverán a alinear los 3 planetas al mismo punto?

Answers

the student of astronauts u know that

may's dog weighed 16kg. the dog lost 800g after it fell ill.

Answers

Answer:

15200g

Step-by-step explanation:

Hope the Dog gets better XD

Answer: 15,200

Step-by-step explanation: First you have to convert kilograms to grams. You have to multiply kilograms by 1,000 to get grams. 16kg*1,000=16,000. Then do this 16,000-800=15,200

Help pls ASAP plssss

Answers

Answer:

y=2x-1

Step-by-step explanation:

The y-intercept is -1

The slope is 2

‏Mr. Jones's prescription calls for 1.04 tablets per day. Based on this information, how many tablets should Mr. Jones take per day? a) 1.25 O b) 1.5 c) 1 O d) 2
I think the answer is a but I'm not sure I'm really a little confused I want to check with this app please can someone heelp me

Answers

I think it’s C because 1.04 is closest to 1

How much time will it take Wilson to finish painting the bookcase? Explain.

Answers

He will take 50 minutes.
To complete it’ll be 100%.
So if you multiple 20 times 2 it’ll give you 40…which will now have you at 80% So you need 20% left which is half of 40% to complete the 100% which will be half of 20 which is 10. Then you add to the 40 you alr have which sum up to 50min total!!!

Question 8 of 10 What is sin 30º? 60 2 901 D A B. c.. () E. E )​

Answers

Answer:

A.  [tex]\displaystyle \frac{1}{2}[/tex]

General Formulas and Concepts:

Trigonometry

[Right Triangles Only] SOHCAHTOA  [Right Triangles Only] sinθ = opposite over hypotenuse

Step-by-step explanation:

Step 1: Define

sin 30°

Step 2: Solve

Since sin is opposite over hypotenuse, we need to find the length of the opposite leg of the angle and the length of the hypotenuse.

Given the triangle and it's values, the opposite leg to the 30° angle is 1 and the hypotenuse is 2.

Substituting it into sin, we have:

sin 30° = 1/2 = 0.5

∴ our answer is A.

12
Fill in the blank: What's the length of the missing
side?
Ilype your answer

Answers

Answer:

13

Step-by-step explanation:

Using Pythagoras Theorem:

[tex]a^2+b^2=c^2[/tex]

Substitute values of a and b:

[tex]5^2+12^2=25+144=169[/tex]

[tex]c^2=169\\c=13[/tex]

The length of the missing side is 13.

The pair of points (-4, y) and (5, 7) lie on a line with slope 1/3. What is the value of y? You must show all of your work to receive credit

Answers

Answer:

4

Step-by-step explanation:

[tex]slope = \frac{y - 7}{ - 4 - 5} = \frac{1}{3} [/tex]

y-7=-3, then y=4

Keith’s Florists has 15 delivery trucks, used mainly to deliver flowers and flower arrangements
in the Greenville, South Carolina, area. Of these 15 trucks, 6 have brake problems. A sample
of 5 trucks is randomly selected.
a. What is the probability that 2 of those tested have defective brakes? (5 marks)
b. Is this a discrete or continuous distribution? Explain.

Answers

Answer:

= 0.419

Step-by-step explanation:

in pic  

(Hope this helps can I please have brainlist (crown)☺️)

PLEASE ANSWER THESE ASAP WITHIN THIS HOUR!
80 is what percent of 400?
a. Base
b. Rate
c. Percentage

16% of what number is 56?
a. Base
b. Rate
c. Percentage

16% of what number is 56?
a. Base
b. Rate
c. Percentage
Thank you for your help <33

Answers

Answer:

♦ 80 is what percent of 400?

a. Base

b. Rate

c. Percentage

Answer: b. Rate

Solution:-

80 = x% of 400x% × 400 = 80x/100 × 400 = 804x = 80x = 80/4x = 20

80 is 20% of 400 ( the rate is the percent)

♦ 16% of what number is 56?

a. Base

b. Rate

c. Percentage

Answer: a. Base

Solution:-

16% of x = 5616/100 × x = 5616x/100 = 5616x = 56 × 100x = 5600/16x = 350

16% of 350 is 56 (The base is the amount which you're taking a percent of)

7<2m-23 what is the answer if someone knows

Answers

Answer:

the answer is m > 15.

hope this helps!

Find the half-life, in days, of Co-60. Round your
answer to the nearest tenth.
Cobalt-60 is used in the treament of
cancer. A sample contains 8 grams of Co-
60 where k = 0.1308.
Enter the correct answer.
N = Noe -kt
DONE
No = initial mass (at time t = 0)
DOO
(อ
N = mass at time t
k = a positive constant that depends on
the substance itself and on the units
used to measure time
t = time, in days

Answers

Answer:5.3

Step-by-step explanation:

Why

Divide both sides by 8

4=8e ^-0.1308t

0.5=e^-0.1308t

Take log of both sides

In0.5=Ine^-0.1308t

Apply In e^x=x

In0.5=-0.1308

Divide both sides by -0.1308 to solve for t

t=5.3

Find the equation of the line passing through the point (-5,2) with slope 1/3. Show work.

Answers

Hello!

First, let's write our equation in point-slope form.

Point-Slope Form:

y-y1=m(x-x1)

y1= the y-coordinate of the point

m=the slope

x=the x-coordinate of the point

y-2=1/3(x-(-5)

y-2=1/3(x+5)

y-2=1/3x+5/3

y=1/3x+5/3+2

y=1/3x+3.7

Hope it helps.

~A smiley teen

#CarryOnLearning

[tex]MagicalNature[/tex] here to help

Simplify the following expression
3x + 2(x +6) -4 -2x

A. 3x + 2
B. 7x + 8
C. 3x + 8
D.7x + 10

Answers

Answer:

C

Step-by-step explanation:

3x+2(x+6)-4-2x.

First, we do the parenthesis.

This gives us: 3x+2x+12-4-2x.

Then, we reorder so like terms are together.

This gives us: 3x+2x-2x+12-4.

Then, we combine like terms.

This gives us: 3x+8, which is C.

Find the distance between the points (–1∕2,–8) and (–1∕2,–2). Question 11 options: A) 6 B) 1∕2 C) 8 D) 10

Answers

The answer is option D, 10. By using the distance formula this is what you should get.

Check the picture below.

sole the inequality x-8>-4

Answers

Answer:

[tex]x>4[/tex]

Based on this, we know the correct number line will be an empty bubble with a line going to the right of 4.

Step-by-step explanation:

[tex]x-8>-4[/tex]

add 8 to both sides of the inequality

[tex]x>4[/tex]

Help with this one please

Answers

[tex]\huge \bf༆ Answer ༄[/tex]

The Translation can be expressed as : -

A Translation -

up 3 units and left 4 units

[tex]꧁  \:  \large \frak{Eternal \:  Being } \: ꧂[/tex]

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