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
Sveta_85 [38]
3 years ago
14

A 20mg sample of thorium-233 decays to 17mg after 5 min. determine the half life of thorium-233?

Mathematics
1 answer:
snow_tiger [21]3 years ago
3 0
Let r be the decay rate (time in minutes) 17 = 20 e^(5r) 0.85 = e^(5r) ln 0.85 = 5r similarly, ln 0.5 = hr ... where h is the half-life, so dividing the 2 equations, ln 0.85 / ln 0.50 = 5r / hr = 5/h h = 5 ln 0.50 / ln 0.85 h = 21.3 min b) 1/20 = 0.05, so ln 0.85 = 5r ln 0.05 = tr t = 5 ln 0.05 / ln 0.85 t = 92.2 min
You might be interested in
When does expanding and simplifying a(b+c) result in a positive value for ac
TiliK225 [7]

Answer:


Step-by-step explanation:

(ab + bc)(ab + bc)

Simplifying

(ab + bc)(ab + bc)

Multiply (ab + bc) * (ab + bc)

(ab(ab + bc) + bc(ab + bc))

((ab * ab + bc * ab) + bc(ab + bc))

Reorder the terms:

((ab2c + a2b2) + bc(ab + bc))

((ab2c + a2b2) + bc(ab + bc))

(ab2c + a2b2 + (ab * bc + bc * bc))

(ab2c + a2b2 + (ab2c + b2c2))

Reorder the terms:

(ab2c + ab2c + a2b2 + b2c2)

Combine like terms: ab2c + ab2c = 2ab2c

(2ab2c + a2b2 + b2c2)

7 0
3 years ago
What is the slope intercept form for y-5=3(x-3)
zubka84 [21]

Answer:y=3x-4

Step-by-step explanation:

you add 5 on both sides

simplify

and get y on one side

slope is 3

the y intercept is -4

4 0
2 years ago
1. What is the slope of the line tangent to the curve defined by y2 + xy - x2 = 11x at the point (2, 3)?
andreyandreev [35.5K]

Step-by-step explanation:

By using Implicit Differentiation,

d/dx (y² + xy - x²) = d/dx (11x)

d/dx (y²) + d/dx (xy) - d/dx (x²) = 11

2y * dy/dx + x * dy/dx + y - 2x = 11

dy/dx (2y + x) = 11 + 2x - y

dy/dx = (11 + 2x - y) / (2y + x).

At the point (2, 3), we have x = 2, y = 3.

=> dy/dx = (11 + 2(2) - (3)) / (2(3) + (2))

= 12 / 8 = 1.5.

P.S. Your question is weird because (2,3) is not on the graph, let me know what is the correct question thanks!

7 0
2 years ago
If f(x) = 3x - 16, evaluate f(-2)
babymother [125]

Answer:

3(-2)-16

-6-16= -22

answer: -22

7 0
3 years ago
How Do you Simplify Fractions? For example: 4 over 5 + 3 over 5
vova2212 [387]
If I am not mistaken, you cross multiply then divide.
8 0
3 years ago
Read 2 more answers
Other questions:
  • When the Slowpoke Marathon began, the ratio of runners to joggers was 2 to 19. A total of 4200 participants began the race (each
    15·2 answers
  • What is the value of k(-6)<br> Please help!!!
    12·1 answer
  • 17n – 5n2 + 2n3; n = -1<br> I need help plz
    7·2 answers
  • Use Gauss's approach to find the sum for 1+2+3+4+...+999
    10·2 answers
  • Please help!! I need the answer!!
    14·1 answer
  • 22 more than four times a number is less than 82 <br><br> (Inequality equation)
    9·1 answer
  • –2x2 – 12x – 9 = 0 PLS HELP I DO NOT WANT TO FAIL I WILL GIVE BRAINLIEST
    10·1 answer
  • PLEASE HELP ME WITH THESE TWO QUESTIONS PLEASE
    5·2 answers
  • K is the midpoint of VW.<br> If KV = 3x and KW = 5x-10, what is VW?<br> 22.5<br> 15<br> 7.5<br> 30
    12·1 answer
  • ILL BRAINLIEST YOU IF YOU PLEASE HELP ME
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!