the half life of c14 is 5730 years. Suppose that wood found at an archeological excavation site contains about 35% as much C14 as does living plant material. Determine when the wood was cut

Answers

Answer 1

Answer:

The wood was cut approximately 8679 years ago.

Step-by-step explanation:

At first we assume that examination occured in 2020. The decay of radioactive isotopes are represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of mass in time, measured in miligrams per year.

[tex]\tau[/tex] - Time constant, measured in years.

[tex]m[/tex] - Mass of the radioactive isotope, measured in miligrams.

Now we obtain the solution of this differential equation:

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{1}{\tau} + C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

And time is cleared within the equation:

[tex]t = -\tau \cdot \ln \left[\frac{m(t)}{m_{o}} \right][/tex]

Then, time constant can be found as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 5730\,yr[/tex] and [tex]\frac{m(t)}{m_{o}} = 0.35[/tex], then:

[tex]\tau = \frac{5730\,yr}{\ln 2}[/tex]

[tex]\tau \approx 8266.643\,yr[/tex]

[tex]t = -(8266.643\,yr)\cdot \ln 0.35[/tex]

[tex]t \approx 8678.505\,yr[/tex]

The wood was cut approximately 8679 years ago.


Related Questions

–8(n + 7) >-96??????????????

Answers

Answer:

D) n<5

Step-by-step explanation:

if angle 4 equals 50 degrees find the measure of angle 5 will mark brainiest​

Answers

Answer:

∠5 = 50°

Step-by-step explanation:

its alternate internal angles:

∠4 ≅ ∠5 (angle 4 is congruent or equal to alternate internal angle)

therefore,

∠5 = 50°

The measure of angle 5 should be considered as the 50 degrees when angle 4 should be equivalent to 50 degrees.

What is alternate internal angles?

Alternate interior angles should be created via intersecting the 2 parallel lines in a transversal way. It should be located that lies between the two parallel lines.

Since the given diagram shows the alternate internal angles

Since angle 4 is 50

So angle 4 should be congruent or equivalent to alternate internal angle)

So angle 5 should be 50 degrees.

learn more about an angle here: https://brainly.com/question/21103473

Select two ratios that are equivalent to 27:927:927, colon, 9. Choose 2 answers: Choose 2 answers: (Choice A) A 3:13:13, colon, 1 (Choice B) B 9:39:39, colon, 3 (Choice C) C 6:36:36, colon, 3 (Choice D) D 9:69:69, colon, 6 (Choice E) E 12:312:3

Answers

Answer:

A. [tex]Ratio = 3:1[/tex]

B. [tex]Ratio= 9:3[/tex]

Step-by-step explanation:

Given

[tex]Ratio= 27:9[/tex]

Required

Determine equivalent ratios:

[tex]Ratio= 27:9[/tex]

First, we simplify the ratio to the least possible

[tex]Ratio = 27/9:9/9[/tex]

[tex]Ratio = 3:1[/tex]

By comparison with the given options, we have A and B as answer.

See Proof Below

Proof: A

Compare this to the simplified ratio (given), we have:

[tex]Ratio = 3:1[/tex] = [tex]Ratio = 3:1[/tex]

Proof B

[tex]Ratio= 9:3[/tex]

Simplify the ratio to the least possible

[tex]Ratio= 9/3:3/3[/tex]

[tex]Ratio= 3:1[/tex]

Compare this to the simplified ratio (given), we have:

[tex]Ratio = 3:1[/tex] = [tex]Ratio = 3:1[/tex]

Answer:

9:3 and 3:1

Step-by-step explanation:

I just did this lesson

what is the midpoint of the line segment (-6,3) (-10,7)

Answers

Answer:

(-8,5)

Step-by-step explanation:

its what comes in between the two

3. Suppose a country consists of 35 states, each of which is assigned a certain number of electoral votes. How many vote orders would we need to consider in order to calculate the Shapley-Shubik index for each state?

A) 2^35
​ B) 2^35–1
C) 35!
D) 35! –1

Answers

Answer:

The answer to this would be 2^35-1

Step-by-step explanation:

The Complex Conjugate of 2 + 5i is equal to: _______+_________i

Answers

Answer:

2 - 5i

Step-by-step explanation:

For any complex number like say "z" written in rectangular form as;

z = a + ib, then from definitions the complex conjugate is given by the relation:

z* = a − ib

Now, from our question, we want to find the complex conjugate of 2 + 5i.

From the relationship above, it's clear that the complex conjugate here is;

2 - 5i

find the value of x. PLEASE HELP!!!!!

I need to show my work.

Answers

Answer:

x-60

Step-by-step explanation:

Well the expressions lie on a straight line so I know that both of the added together will equal 180.

So the equation looks like this-(x-1+2x+1=180)

So when I substitute 60 in the equation it looks like this-(60-1+2(60)+1=180)

To solve-60-1+120+1::59+120+1::60+120

180

There are 5 chairs to every 2 tables in class. Which ratio is equivalent to 5:22
35:14
15:12
10:6
40:18

Answers

Answer:if your meaning 5:2 the answer would be 35:14

Step-by-step explanation:

You simply would have the find the equal to it so by multiplying both by 7 would make it equal. 7 × 5 is 35 and 7 × 2 is 14

5/8 divided by 1/4 I would like to see how smart you all are?

Answers

Answer:

2.5

Step-by-step explanation:

good luck :)

I think it’s like uh so you divide them and get 2

Point A is located at negative 6 over 8 and point B is located at negative 1 over 8. What is the distance between points A and B? negative 6 over 8 plus negative 1 over 8 = negative 7 over 8; therefore, the distance from A to B is absolute value of negative 7 over 8 equals negative 7 over 8 units negative 6 over 8 plus negative 1 over 8 = negative 7 over 8; therefore, the distance from A to B is absolute value of negative 7 over 8 equals 7 over 8 units negative 6 over 8 minus negative 1 over 8 = negative 5 over 8; therefore, the distance from A to B is absolute value of negative 5 over 8 equals negative 5 over 8 units negative 6 over 8 minus negative 1 over 8 = negative 5 over 8; therefore, the distance from A to B is absolute value of negative 5 over 8 equals 5 over 8 units

Answers

Given:

Point A is located at [tex]-\dfrac{6}{8}[/tex].

Point B is located at [tex]-\dfrac{1}{8}[/tex].

To find:

The distance between points A and B.

Solution:

We know that,

Distance between points A and B = Location of A - Location of B

Using this given values, we get

Distance between points A and B [tex]=-\dfrac{6}{8}-\left(-\dfrac{1}{8}\right)[/tex]

                                                        [tex]=-\dfrac{6}{8}+\dfrac{1}{8}[/tex]

                                                        [tex]=\dfrac{-6+1}{8}[/tex]

                                                        [tex]=-\dfrac{5}{8}[/tex]

Distance cannot be negative. So, we need to find the absolute value of [tex]-\dfrac{5}{8}[/tex].

[tex]|-\dfrac{5}{8}|=\dfrac{5}{8}[/tex]

The distance between A and B is [tex]\dfrac{5}{8}[/tex].

Therefore, the correct option is D.

Write the equation of the line that passes through the points (-9, -3) and (-7, 7). Put your answer in fully reduced point-slope form, unless it is a vertical or horizontal line. क Answer: Submit Answer attempt out of 2 Type here to search O in G​

Answers

Answer:

5x-y +42=0

Step-by-step explanation:

Using m=Y2- Y1

X2- X1

the slope of the line is found .

Put your answer in Y - Y1 = m( X - X1)

to get the equation

A satellite 200 miles above the earth is orbiting the earth once every 6 hours. How far does the satellite travel in 1 hour?
(Assume the radius of the earth is 4,000 miles.) Give your answer as both an exact value and an approximation to three significant digits

Answers

Answer:

The answer is below

Step-by-step explanation:

Speed is the ratio of total distance travelled to total time taken to cover distance.

The radius of the orbit = radius of earth + height of satellite from earth = 4000 miles + 200 miles = 4200 miles

The total distance around the orbit = perimeter of orbit = 2π(radius of orbit) = 2π(4200) = 8400π miles

[tex]Speed=\frac{distance \ traveled}{time\ taken} =\frac{8400\pi\ miles}{6\ hours} =1400\pi\ miles/hour\\\\Distance \ traveled\ in \ 1\ hour=1400\pi\ miles/hour*1\ hour=1400\pi\ miles=4398.23\ miles\\\\Distance=4398\ miles[/tex]

What would x be in px + 3 = k

Answers

Answer:

Step-by-step explanation:

k=3

Suppose that 28 crayons, of which four are red, are divided randomly among Jack,Marty, Sharon, and Martha (seven each). If Sharon has exactly one red crayon, what is the probability that Marty has the remaining three?

Answers

Answer:

0.0263

Step-by-step explanation:

Solve for the variable : 5y+6=3(y+4)

Answers

Answer:

y = 5

Step-by-step explanation:

Answer:

Y=3

Step-by-step explanation:

You would want to multiply y and 4 by 3.

5y+6=3(y+4)

×3 ×3

5y+6=3y+12

Now you want to have y by itself. You can first subtract 6 for starters.

5y+6=3y+12

-6 -6

5y=3y+6

5y=3y+6

-3y -3y

2y=6

Now you would want to divide.

2y=6

÷2 ÷2

y=3

You're answer would be y=3.

Robinson's Doughnut Factory produces 21,600 doughnuts every day. They

have a fleet of 9 delivery trucks. If the doughnuts are divided evenly, how

many doughnuts will be loaded onto each truck?

Answers

Answer:

2400 doughnuts

Step-by-step explanation:

Given that,

Robinson's Doughnut Factory produces 21,600 doughnuts every day.

No. of delivery trucks = 9

We need to find the no of doughnuts will be loaded onto each truck. Let there are n doughnuts. It can be calculated by dividing 21,600 by 9.

So,

[tex]n=\dfrac{21600}{9}\\\\n=2400[/tex]

So, there are 2400 doughnuts that will be loaded onto each truck.

.
Gina has been offered a job as a dog walker. The job pays $10 each week plus $5 per dog walked. Gina’s goal is to earn $75 each week. What is the number of dogs Gina must walk in order to reach her weekly goal?

Answers

Answer:

13

Step-by-step explanation:

write a verbal expression for x+y

Answers

Answer:

x plus y

Step-by-step explanation:

self explainatory

What is the answer for number 6

Answers

Answer:

x=6

Step-by-step explanation:

x−7=13

Step 1: Add 7 to both sides.

x−7+7=13+7

x=20

Answer:

x=20

Equivalent Expressions

Warm-Up

Active

Evaluating an Expression

Complete the statements.

Evaluate (15 - 4x) + 5 when x = 3.

Substitute the given value for the

Evaluate within

parentheses.

to simplify.

Use the

inside the

Evaluate exponents.

First, complete the

parentheses.

Next, complete the

parentheses.

Last, complete the addition.

inside the

Multiply and divide

from left to right.

The value is

Add and subtract

from left to right.

Answers

Answer:

Complete the statements.

Substitute the given value for the

✔ variable

.

Use the

✔ order of operations

to simplify.

First, complete the  

✔ multiplication

inside the parentheses.

Next, complete the

✔ subtraction

inside the parentheses.

Last, complete the addition.

The value is

✔ 8

.

Step-by-step explanation:

Plz give me brainlest

Answer:

Variable, order of operations, multiplication, subtraction, 8.

Step-by-step explanation:

Got it right Edge2021

What is the area of a rectangle with width 5x and length x2 + 4x + 4?

Answers

Answer:

It's 18

Step-by-step explanation:

Answer:

18

Step-by-step explanation:

What is the real part of the complex number when 4 plus 5i is multiplied with 2 minus i?
3 + 6i
13 + 6i
13
3
6
6i

Answers

Answer:

What I do not understand what you are asking, can you repeat it pls.

Step-by-step explanation:

Find the exponential function that satisfies the given conditions: initial value = 70, decreasing at a rate of 0.43% per week

Answer choices:
A) f(t) = 70 x 0.9957^t
B) f(t) = 70 x 1.43^t
C) f(t) = 0.43 x 0.3^t
D) f(t) = 70 x 1.0043^t

Answers

B) f(t) = 70 x 1.43^t

function f(x) has a slope of 3/2 and a y-intercept of 6. explain how the graph of f(x) could be used to find the x-intercept

Answers

Answer:

x - intercept = -4

Step-by-step explanation:

We are told the function f(x) has a slope of 3/2 and a y-intercept of 6.

From general line equation, the formula is; y = mx + c

Where m is the slope and c is the intercept.

Thus, the equation is;

f(x) = (3/2)x + 6

Now,to find the x-intercept on the graph, it will be at a point where f(x) = 0.

Thus let's put 0 for f(x) to find the x-intercept.

0 = (3/2)x + 6

(3/2)x = -6

x = -6 × 2/3

x = -4

Answer:

x=(x-4)

Step-by-step explanation:

Find the x-coordinate of the point that crosses the x-axis. The x-intercept is -4

Two people start walking at the same time in the same direction. One person walks at 8 mph and the other

person walks at 3 mph. In how many hours will they be 1.25 miles apart?

Answers

Answer:

0.25hours  

Step-by-step explanation:

Data

speed v1=8mph

speed v2=3mph

distance= 1.25

time t=?

speed= distance/time

distance=speed*time

1.25=8*t-3*t

1.25=8t-3t

1.25=5t

t=1.25/5

t=0.25hours

In minutes it is 15min

-A clock's battery is running low. Every 6 hours, its slows down by 1/2 hour. By how much did it slow
down in 1 hour?

Answers

Hi!

If its running low and every six hours it slows down half an hour, we need to divide 6  from 1/2 (or in another form if you have a regular calculator, 0.5).

6 divided by 1/2 is 12 (or , in decimal form).

So your answer would be: It will slow down 12 minutes every hour.

Hope this helps!

What makes rational algebraic expression undefined?
a. When the numerator becomes 0
b. When the denominator becomes 0
c. When the value of the given variable is equal to O
d. When the restricted value is equal to 0​

Answers

Answer:

The answer is B.

Answer:

when denominator becomes zero 0

I need help with question 11 pleaseeeeeee

Answers

The base of the prism is a 3:4:5 right triangle.
One of the legs is its base and the other is its height. (The longest side is the hypotenuse!)

The area of the triangular base is bh/2 = (9)(12) / 2. There are two of these.
There are also three rectangular sides on the prism.
Their dimensions are 9 by 20, 12 by 20, and 15 by 20.

You can do the arithmetic from here.
And the answer is 828cm ^2

Answer:

828 cubic units

Step-by-step explanation:

Is 3 cups to 2 cups proportional

Answers

No it should be 3:3 or 2:2 because you have to be able to divide them and get a 1:1 ratio

Find the distance between Rockville and San Jose if they are in apart on a map with a scale of 2in:
25 mi

Answers

Answer with step-by-step explanation:

The distance between Rockville and San Jose is 2407.2. Since there are 63360 inches in a mile, we divide it by 2, which is 31680. We multiply 2407.2 by 31680, and get 76260096.

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