1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
bixtya [17]
3 years ago
7

Cobalt-56 has a decay constant of 8.77 × 10-3 (which is equivalent to a half life of 79 days). How many days will it take for a

sample of cobalt-56 to decay to 62% of its original value? (At = A0e-kt)
Mathematics
1 answer:
ANEK [815]3 years ago
7 0
So we want to know how long will it take cobalt 56 to decay to 62% to it's original value if we know that one half life is T₁/₂=79 days and it's decay constant is k=8.77*10^-3. The law for radioactive decay is:

N(t)=N₀e^-k*t, where N(t) is the quantity of the material in some time t, N₀ is the original quantity of the material, k is the decay constant, t is time. 

N(t)=0.62*N₀ or 62% of the original value. 
0.62*N₀=N₀e^-k*t, N₀ cancel out and we get:

0.62=e^-k*t

We need to get the time t. We get t if we take the natural logarithm of both sides: 

ln(0.62)=-k*t*ln(e), ln(e)=1 so we have:

ln(0.62)=-k*t

t={ln(0.62)/(-k)} = 54.5. 

Time for cobalt 56 to decay to 62% of its original value is 54.5 days. 
You might be interested in
4 1/8 c = __ fl oz help plz
bija089 [108]
33 fl ounces

Work: 4 1/8 • 8
4 0
3 years ago
Part A: Factor x2b2 − xb2 − 6b2. Show your work. (4 points)
IrinaVladis [17]
PART A. Notice that we have b^{2} as a common factor in all the terms, so lets factor that out:
x^{2} b^2-xb^2-6b^2
b^2(x^{2} -x-6)
Now we need can factor x^{2} -x-6:
b^2(x^{2} -x-6)
b^2(x+2)(x-3)

We can conclude that the complete factorization of x^{2} b^2-xb^2-6b^2 is b^2(x+2)(x-3).

PART 2. Here we just have a quadratic expression of the form a x^{2} +bx+c. To factor it, we are going to find <span>two numbers that will multiply to be equal the </span>c<span>, and will also add up to equal </span><span>b. Those numbers are 2 and 2:
</span>x^{2} +4x+4=(x+2)(x+2)
Since both factors are equal, we can factor the expression even more:
x^{2} +4x+4=(x+2)^2

We can conclude that the complete factorization of x^{2} +4x+4 is (x+2)^2.

PART C. Here we have a difference of squares. Notice that 4, can be written as 2^2, so we can rewrite our expression:
x^2-4=x^2-2^2
Now we can factor our difference of squares like follows:
x^{2} -2^2=(x+2)(x-2)

We can conclude that the complete factorization of x^2-4 is (x+2)(x-2)
7 0
3 years ago
An airport has two long term parking lots. the cost to park,y, in each lot for x days is shown in the tables
Licemer1 [7]

Answer:

y = 4x + 12 will be the other equation.

Step-by-step explanation:

Data given in the tables show a linear relation (has a common data).

To get the linear relation, we will choose the two points from table (1) .

Let the points are (1, 16) and (2, 20).

Slope of the line 'm' = \frac{\triangle{y}}{\triangle{x}}

m = \frac{20-16}{2-1}

m = \frac{4}{1}

m = 4

Equation of the line passing through (1, 16) having slope = 4

y - 16 = 4(x - 1)

y = 4(x - 1) + 16

y = 4x - 4 + 16

y = 4x + 12

Now we take second set of data,

We choose two points (1, 6) and (2, 12).

Slope 'm' = \frac{\triangle{y}}{\triangle{x}}

m = \frac{12-6}{2-1}

m = 6

Equation of the line passing through (1, 6) having slope = 6

y - 6 = 6(x - 1)

y = 6x - 6 + 6

y = 6x

Therefore, other equation of the system of equations will be,

y = 4x + 12

8 0
3 years ago
(-8, 4), (4, -4)<br> Write in standard form
Serjik [45]

Answer written in standard form:

2x + 3y = -4

7 0
3 years ago
Read 2 more answers
A recipe shows that the yeast needed for a bread recipe is 2 1/2ounces. Which of the following decimals is equivalent to this nu
UkoKoshka [18]

Answer:

C. 2.3 repeated

Step-by-step explanation:

1/3 doesn't equal a (what you could say is) regular decimal. It repeats because it does not evenly go into 10 or 100

7 0
3 years ago
Read 2 more answers
Other questions:
  • I NEED HELP ASAP PLEASE
    5·2 answers
  • Solve the following system of equations: y=x+4 2x+y=13
    14·2 answers
  • Identify the coefficient of <br> -24×7y
    7·2 answers
  • HELP ME PLEASE SOMEONE
    9·1 answer
  • Susan makes 5 fruit cups for the picnic. In each cup, she has 5 strawberries and 3 kiwi. Joanna uses the same number of total fr
    5·2 answers
  • 2^4x4^4=2^4x2^n=2^12
    14·1 answer
  • 7.1 Pythagorean Theorem ​
    12·1 answer
  • 18 landmarks in 12 3/4 days how many days to do 12 landmarks?
    7·1 answer
  • dominique and ella are comparing whose jet traveled faster. The graph shows the relationship between the total distance Dominiqu
    15·1 answer
  • How do you write 8/5 as a percentage
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!