answer.
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
Semmy [17]
2 years ago
11

How long will it take before twenty percent of our 1,000-gram sample of uranium-235 has decayed? [See Section 6.6 Example 13] Th

e decay equation is A(t)=A_0e^{Kt} , where t is the time for the decay, and K is the characteristic of the material. Suppose T is the time it takes for half of the unstable material in a sample of a radioactive substance to decay, called its half-life. Prove that K= \frac{ln0.5}{T} . What is T for the uranium-235? Show the steps of your reasoning.
Mathematics
1 answer:
horsena [70]2 years ago
8 0

Answer:

From what I can see of the problem, you CANNOT solve for the half-life of U 235 AND then solve for the length of time to determine the 20% decay.

U-235 half-life is 704,000,000 years. (Wikipedia)

The elapsed time formula = half-life * [log (Beginning Amount / ending amount) / log 2]

elapsed time = 7.04 x 10^8 * [log (100 % / 80%) / log 2]

elapsed time =7.04 x 10^8 *  [log (1.25) / .30103]

elapsed time =7.04 x 10^8 *  [0.096910 / .30103]

elapsed time = 7.04 x 10^8 *  0.321928047

elapsed time = 226,637,000 years

Step-by-step explanation:

You might be interested in
If the 180 food calories found in a granola bar come entirely from p grams of protein, f grams of fat, and c grams of carbohydra
Mice21 [21]

f = 180 - p - c

to find the amount of fat subtract the protein and carbs from the original 180 calories

3 0
2 years ago
Read 2 more answers
The perimeter of the school crossing sign is 102 inches what is the length of each side
Afina-wow [57]
The perimeter of the school crossing sign is 102 inches
length of each side = ?
in the question number of sides is not mentioned, so the answer may vary for the length of each side. if there is 5 sides divide 102 by 5, we get 20.4 answer so in case of 5 sides length of each side is 20.4 inches. if there is 4 sides divide 102 by 4 and we get 25.5 inches answer for the legnth each side.
6 0
2 years ago
This unit focused, in part, on relationships in triangles. A triangle is the simplest type of polygon and is frequently used in
Galina-37 [17]
The answers are as follows:
1. Triangles are often used to build different types of support structures because of its beneficial properties. Triangles is rigid in shape and it has strength. When force is applied to the side of a triangle, it can not shift into another shape, this is because its sides and angles are fixed. 
2. The properties of triangle that make it a desirable geometric shape for building support structures is its fixed sides, fixed angles, rigidity and strength. Triangles are the strongest shapes and they are stable. Thus, triangle can be easily fix together to provide strength and stability over a wide area.
3. There are different types of triangles, these include: equilateral triangle, scalene, isosceles, right triangle, obtuse and acute. Of all these triangles, the best triangle is equilateral triangle.  
4. Triangle is preferred over other types of polygon because, it is the strongest. The other polygons can be bent into different other forms that are not regular polygon, but a triangle always retains its shape and can not be deformed.
6 0
2 years ago
Read 2 more answers
Caswell started studying how the number of branches on his tree grows over time. The relationship between the elapsed time ttt,
ipn [44]

Answer:

t =log(20) / 0.3 = 10*log(20) / log(1,000) - years - when the tree will have 100 branches.

Step-by-step explanation:

100 = 5 * 10^(0.3t), solve for t

Divide both sides by 5:

20 =10^(0.3t)

Take the log of both sides:

0.3t =log(20)

Divide both sides by 0.3:

Multiply the RHS by 10 / 10

t =log(20) / 0.3 = 10*log(20) / log(1,000) - years - when the tree will have 100 branches.

8 0
2 years ago
Read 2 more answers
Evaluate 6+3b if b=7
Pavlova-9 [17]
27. Replace b with 7, making 6 + 3(7). The 3 and parentheses of 7 hint multiplication, so you multiply to make 21, then add 6 relating back to PEMDAS to teach you the correct order to solve the problem.
6 0
2 years ago
Read 2 more answers
Other questions:
  • Lori creates the following design for a T-shirt.
    6·1 answer
  • Eli needs pieces of ribbon cut into strips that are 2 1\2 feet long. The roll of ribbon is 7 1\2 feet long. Which expression cou
    7·2 answers
  • 2 Rita bought three and forty-eight hundredths pounds of bananas at the store. How is this number written in expanded notation?
    9·1 answer
  • Stefan's family rented a rototiller to prepare an area in their backyard for spring planting. The rental company charged an init
    5·2 answers
  • Mr and Mrs Thomas buy tickets for themselves and their four children The cost of an adult ticket is £7 more than the cost of a c
    10·1 answer
  • In 2015, there were about 22 million teenagers (aged 13–17) in the United States. They each sent an average of 900 text messages
    11·1 answer
  • What is the following sum? 2 (RootIndex 3 StartRoot 16 x cubed y EndRoot) + 4 (RootIndex 3 StartRoot 54 x Superscript 6 Baseline
    6·2 answers
  • A manufacturer produces three models of bicycles. The times (in hours) required for assembling, painting, and packaging each mod
    12·1 answer
  • HELP!!<br> What is the equation of the circle shown in the graph?
    9·1 answer
  • At a restaurant, when a customer buys four pretzels the fifth pretzel is free. soft pretzels cost $3.90 each. you ordered 12 sof
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!