If the activity of a source is 70 Bq after 2 years, and 35 Bq after 15 years. How long will be until the activity is 8.75 Bq?​

Answers

Answer 1

Answer:

N = N0 e^-kt          calling k the decay constant

70 = N0 e^-2 kt

35 = N0 e^-15 k

2 = e^(-2 + 15) k

.693 = 13 k

k = .0533

N0 = N e^kt

N0 = 70 e^(.0533 * 2) = 77.87

8.75 = 77.87 e^-(.0533 t)

ln .1124 = -.0533 t

t = -ln .1124 / .0533 = 41 yr


Related Questions

Please help I’ll mark brainlyest

Answers

Answer:

10N right

Explanation:

The 10N of force acting down and up on the object cancel out.

The 15N of force pulling the force to the right is stronger than the 5N of force pulling the object left

15N - 5N = 10N

The magnitude and unit is 10N, and the direction is right

although the pivot exerts a force on the ruler it does not exert a torque with respect to the pivot point. why not?

Answers

Answer:

The situation is not shown, however if one calculates torques about the pivot point, then the pivot point itself exerts no torque because the force applied by the pivot point exerts zero torque because Fp * L = 0 where L = 0 in this case.

If one wants to calculate torques about, say, the end of the ruler then one would need to calculate the torque applied by the pivot point.

What would happen if the mass of Venus doubled?

Answers

Answer:

it will start moving faster and may also move away from the sun..

or if it's speed decreases it will go towards the sun and will collapse with it

brainliest plz

Hi I just need an answer btw it’s science not physics

Answers

Answer:

You need to divide 200 by 23 seconds in order to get your answer.

A cheetah running initially at a velocity of 20 m/s accelerates
uniformly at 3.0 m/s. The velocity of the cheetah will be
m/s after 4.0 seconds.

Answers

Answer: I think it’s 32 m/s

Explanation: Vi=20 m/s

Vf=?

a=3.0 m/s^2

t= 4s

Vf= Vi + at

Vf= 20 m/s + (3 m/s^2)(4s)

Vf= 20 m/s + 12m/s

Vf= 32m/s

If A cheetah running initially at a velocity of 20 m/s accelerates

uniformly at 3.0 m/s2. The velocity of the cheetah after 4.0 seconds will be 32 m/s.

To find the velocity of the cheetah after some time we can use the formula:

v = u + at

where:

v = final velocity

u = initial velocity

a = acceleration

t = time

Given:

Initial velocity (u) = 20 m/s

Acceleration (a) = 3.0 m/s²

Time (t) = 4.0 seconds

now we can put values in eq.

v = 20 m/s + (3.0 m/s²) * 4.0 s

v = 20 m/s + 12 m/s

v = 32 m/s

so the answer is 32 m/s.

To learn more about Acceleration, here:

brainly.com/question/2303856

#SPJ3

Can someone help me with one through seven I will mark you the brainly

Answers

Answer:

1.  F = M x A

2. Force  

3. 2nd Law: Force

4. a, b, c (in order)

5. 3rd Law: Action and Reaction

6. b, c, a (in order)

7. 1st Law: Inertia

1. F=ma

2. Force

3. Second law

4. a)first

b)second

C) third

5. Third

6. a) second

b) third

C) first

7. First

please help!! i’ll mark you the brainliest answer

A box of mass 4kg is being pulled along a rough surface to the right, as shown below. When F=8N, the box accelerates to the right 1m/s^2. If F is doubled to 16N, the acceleration of the box across the same rough surface will be:

A) 1m/s^2
B) 2 m/s^2
C) 3 m/s^2
D) 4 m/s^2
E) 0.5 m/s^2

Answers

Hi there!

Recall that:

∑F = ma

In the given situation, there is acceleration occurring in the horizontal direction, so there is a net force.

∑F = Fa (Force applied) - Fκ (Force due to kinetic friction)

We can plug in given values to solve for the frictional force:

ma = Fa - Fκ

(4)(1) = 8 - Fκ

4 = 8 - Fk

Fκ= 4N (negative since working opposite to acceleration)

Now, solve given the new force:

4a = 16 - 4

4a = 12

a = 3 m/s², Answer C.

MY PAPER IS DUE IN AN HOUR!!!
Your challenge- Write a paper on how to build, construct, and engineer a faster roller coaster. You essay must contain 5 paragraphs minimum. Each paragraph must be 3 sentences minimum.

Potential energy, Kinetic energy, Thermal energy and friction, speed, velocity, and acceleration, and the law of conservation of energy must be the main ideas of your paragraphs

Answers

Answer:

Your kinetic energy is always proportional to the square of your speed,

no matter whether you're on a bicycle, a roller coaster, or a baby carriage.

The faster you're moving, the more kinetic energy you have.

Your potential energy doesn't depend on speed at all, only on height.

On a roller coaster, the minimum speeds are usually at the top of a hill

or a loop, so the potential energy would generally correspond to the

slowest speeds. But again, that's not because of the speed. It's because

of the height.

Explanation:

What ocean resource may be harvested by vacuuming or trawling?

A. minerals

B. fish

C. fuels

Thank You

Answers

Answer:

B. fish

Explanation:

Vacuuming: to suck up something from the ocean. So in this case it would be sucking up whole fish with huge vacuums.

Acetylene welding goggles are worn because they protect the eyes from

Answers

Answer:

wala

Explanation:wala

the heat and optical radiation produced by the welding

the circular disk rotates about its center. for the instant represented, the magnitude of velocity of a is 8 ft/s and the magnitude of tangential acceleration of b is 9 ft/s2. what is the magnitude of the acceleration of point a?

Answers

Answer:ddddddddddddddd

Explanation:

when was the Hubble telescope launched​

Answers

April 24 1990 is the correct answer

You push the sofa across the floor. Which force is NOT present on the sofa?
a)gravity
b)normal
c)tension
d)applied

Answers

Answer:

c) tension ........ ........

Answer:

gravity

Explanation:

because it cannot be move across if there is present gravity force

constraints for the sub-problem for pollution

Answers

AIR POLLUTION

Hope this helps

Why can we predict the phases of the moon?

please dont search it up

Answers

Answer:

Every year, the moon moves about an inch away

The device that is made up of many single slits that diffract light and form a diffraction pattern , is called

Answers

Gọi là máy quang phổ kế

That's a diffraction grating.


What direction would the net force acting on this box be pointed?
northeast
northwest
southeast
southwest

Answers

Answer:

The diagram shows a net 2 N  in the north direction and 2 N in the east direction - this would result in (4 + 4)^1/2 to the northeast.

Evan drives a golf ball with an initial velocity of 49 meters per second at an angle of 16 degrees own a flat driving range. How far will the golf ball land?

Answers

Answer:

solusion Explanation:the answer in 984

tha

What is a name of a isotope of carbon

Answers

Answer: Carbon 12 :)

Answer:

I've heard of many different names of isotopes of carbon, and they're Carbon-14, Deuterium, Hydrogen-1, Oxygen-18, boron-11, Nitrogen-14, and Neon-20.

__________ invented the analytical engine, a machine that did calculations.

Answers

Answer:

Charles Babbage

Explanation:

Analytical Engine, generally considered the first computer, designed and partly built by the English inventor Charles Babbage in the 19th century (he worked on it until his death in 1871).

if you hold a heavy weight over your head, the work you do __________.

Answers

Answer:

Is zero.

Explanation:

I legit just had this question on my homework.

what is a concentration?​

Answers

Answer/Explanation:

In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration.

A concentration refers to a subject or study within a specific major. As part of the degree coursework, concentration classes count toward your major requirements as well.

22. Calculate the displacement in meters a cyclist would travel in 5.00 h at an average
of 12.0 km/h to the south west

Answers


Explanation:
To whichever direction, if the cyclist did not change the direction, the displacement is
By formula :d=v×t
given, v=12km/h and, t=5h
=>
x=12km/h×5h=60km=60×1000m=60000m

A car of mass 850 kg rests on a slope at 25 to the horizontal. Calculate the magnitude of the component of the cars weight which acts parallel to the slope

Answers

Answer:

plz show the question ❓ by photo

When does the object have potential energy?

Answers

Answer:

To summarize, potential energy is the energy that is stored in an object due to its position relative to some zero position.

Explanation:

An object possesses gravitational potential energy if it is positioned at a height above (or below) the zero height.

what effects does ionizing radiation have on the atmosphere

Answers

What else did you want to do today and you can do homework today and tomorrow morning at school and so we can do

What will happen if a renewable resource is used up faster than it can be
replenished or regenerated? *

Answers

Then it will be replenished

Answer:

there will be no more if a resource is used up you have to find a new aource

If you increase the elasticity of a material, what happens to the speed of a mechanical wave going through it?

Answers

Answer:

At the molecular level, materials are held together by bonds, which act like springs for small displacements from the equilibrium spacing between neighboring atoms. Push the atoms close, the bond pushes back to keep them apart. Pull them apart, the bond pulls the atoms closer. For those small displacements, it acts like a spring

The speed of the wave will be related to the stiffness of of those springs - you compress the material - how quickly do all of those little springs rebound and push their neighboring atoms away, sending that wave of compression through the material.

Explanation:

A 755 N force is used to push a 15 Kg box across the floor. What is the acceleration of the box?

Answers

Answer:

a = 151/3 m/s²

General Formulas and Concepts:

Forces

Newton's 2nd Law of Motion: F = ma

F is force (in N)m is mass (in kg)a is acceleration (in m/s²)

Explanation:

Step 1: Define

Identify variables

F = 755 N

m = 15 kg

Step 2: Solve for a

Substitute in variables [Newton's 2nd Law of Motion]:                                 755 N = (15 kg)aIsolate a:                                                                                                            a = 151/3 m/s²

Topic: AP Physics 1 - Algebra Based

Unit: Forces

A 63 kg boy and sled are pulled along level ground with a force of 577 N. The boy and sled
are moving at a constant velocity of 2.4 m/s. What is the size of the frictional force?

Answers

Answer:

The size of the frictional force is 577 N.

Explanation:

What is frictional force?

Frictional forces are exerted every time you have two surfaces sliding across one another. Friction depends on:

how rougher are the surfaces on contact;how harder you push one surface to the other.

There are two types of friction:

static friction [tex]f_s[/tex];dynamic (sliding) friction [tex]f_d[/tex].

Now let's attack the problem:

First, you have to write the data down:

[tex]\bullet \quad m= 63\,kg\\\\\bullet \quad F= 577\,N\\\\\bullet \quad v= 2.4\,m/s[/tex]

If the boy and the sled moves on constant velocity, Newton's First Law Of Motion states that the net force acting on them must be zero:

[tex]F_{net}=0[/tex]

Applying Newton's Second Law Of Motion, we get:

[tex]F-f_d=0[/tex]

which means that:

[tex]F=f_d[/tex]

In other words, the dynamic frictional force equals the force that moves the boy and sled. So we may write:

[tex]\boxed{f_d=577\,N}[/tex]

Conclusion: the size of the (dynamic) frictional force is 577 N.

Happy studying!

Brainly Team

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