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
Rudik [331]
3 years ago
13

The half-life of cesium-137 is 30 years. Suppose we have a

Mathematics
1 answer:
VMariaS [17]3 years ago
3 0
(a) If y(t) is the mass (in mg) remaining after t years, then y(t) = y(0) e^{kt}=100e^{kt}.

y(30) = 100 e^{30k} = \frac{1}{2}(100) \implies e^{30k} = \frac{1}{2} \implies k = -(\ln 2) /30 \implies \\ \\
y(t) = 100e^{-(\ln 2)t/30} = 100 \cdot 2^{-t/30}

(b) y(100) = 100 \cdot 2^{-100/30} \approx \text{9.92 mg}

(c)
100 e^{- (\ln 2)t/30} = 1\ \implies\ -(\ln 2) t / 30 = \ln \frac{1}{100}\ \implies\ \\ \\
t = -30 \frac{\ln 0.01}{\ln 2} \approx \text{199.3 years}
 
You might be interested in
Quy tắc suy luận nào là cơ sở của suy diễn sau: "Biết rằng: 2 đường thẳng d và d' song song hoặc cắt nhau. Ta đã có d không song
Travka [436]

Answer: a

Step-by-step explanation:

4 0
2 years ago
2x - 3y = -1<br> y = x - 1
Viktor [21]
Here’s how you would work it out

3 0
3 years ago
HELP ME FIND THE ANGLE<br><br><br><br><br> HELP ME FIND ANGLE A
romanna [79]

Answer:

32 degrees

Step-by-step explanation: So they tell you BE is congruent to BC so triangle BCE is isosceles. We know that angle C is 35 degrees and the triangle is isosceles so angle E is 35 degrees too. Now we do 180-(35+35) and that equals 110 so angle B is 110. And we know that angle EBC and FBA are supplementary angles so 180-110 is 70 degrees so angle FBA is 70 degrees and you can do the same thing with angle DFB and AFB so 180-102 degrees is 78 degrees and to find angle a you just do 180-(70+78) and that equals 32 degrees so angle A is 32 degrees. :)

4 0
3 years ago
Graph the parabola 3x^2+6x-24
brilliants [131]
We have the following function:
 F (x) = 3x ^ 2 + 6x-24
 We observe that it is a quadratic equation.
 The graph is therefore a parabola.
 Its cut points are:
 (-4, 0)
 (2, 0)
 Answer:
 
See attached image to see graph of the function

7 0
2 years ago
Can someone please help with this asap its worth a lot of points. (: !!!
ladessa [460]

Answer:

8...the value of d variable =45 degree

corresponding angles are equal(reason)

9.

8 0
3 years ago
Read 2 more answers
Other questions:
  • How much oil wells in a given field will ultimately produce is key information in deciding whether to drill more wells. Data was
    15·1 answer
  • Chris is calculating his deductions for his tax return. He is filing singly. He can claim $1,813 from property taxes, $1,513 fro
    13·1 answer
  • Through what faction of a circle did the minute hand turn
    8·1 answer
  • Calculate y'. xy^4+x^2y=x+3y
    8·1 answer
  • Decide if the following probability is classical, relative frequency, or subjective.You calculate that the probability of random
    7·1 answer
  • F(x) = 2x2<br> Find f(-6)
    14·1 answer
  • meeta's mother is four times as old a Meeta. After five years, her mother will be three times as old as she will be then. What a
    6·1 answer
  • The proportional relationship between the number of hours Lincoln works, h, and his total earnings in dollars and cents, e, can
    6·1 answer
  • 5.5 is what percent of 6.875?​
    9·1 answer
  • ____ : 28 = 42 : 49.
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!