If the activity of a radionuclide decreases from 5,000 disintegrations per minute to 625 disintegrations per minute

in 12 hours, its half-life is?

Answers

Answer 1

Answer:

4 hrs

Explanation:

625 = 5000 (1/2)^n

625/5000 = 1/2^n

n = 3 half lives

3 half lives = 12 hours       1 half life = 4 hrs


Related Questions

As velocity____kinetic energy _____ and potential energy _____

Answers

Answer:

increases   increases   decreases

Explanation:

For an object falling from a height

(02.06 LC)
Etiquette determines which (5 points)

Answers

Answer:

Etiquette determines which behaviors are polite and impolite among players and team. It is a code of polite conduct according to social norms and efficiency. Etiquette as a societal rule is formed to enhance positive human relation when interacting and can reduce conflicts in the society. A person who is aware of the etiquette in a given situation will be more confident, comfortable and competent thus making even those around him or her at ease.

Hello people ~
Which of the following options are correct?
If a conductor has a potential V 4- 0 and there are no charges anywhere else outside, then _____
(a) there must not be charges on the surface or inside itself.
(b) there cannot be any charge in the body of the conductor.
(c) there must be charges only on the surface.
(d) there must be charges inside the surface.

Answers

The charge would be in equilibrium so there would be no charge in the body of the conductor.


Answer:

(b) there cannot be any charge in the body of the conductor

Answer:

B

Explanation:

Note the line that there is no charges anywhere else outside means the charge is placed in equilibrium position.

Hence there cannot be any charge in the body of conductor

A 1,508 kg car rolling on a horizontal surface has a speed of 20.8 km/hr when it strikes a horizontal coiled spring and is brought to rest in a distance of 6.87 m. What is the spring constant (in N/m) of the spring

Answers

Answer:

Approximately [tex]1.79 \times 10^{5}\; {\rm N \cdot m^{-1}}[/tex], assuming friction between the vehicle and the ground is negligible.

Explanation:

Let [tex]m[/tex] denote the mass of the vehicle. Let [tex]v[/tex] denote the initial velocity of the vehicle. Let [tex]k[/tex] denote the spring constant (needs to be found.) Let [tex]x[/tex] denote the maximum displacement of the spring.

Convert velocity of the vehicle to standard units (meters per second):

[tex]\begin{aligned}v &= 20.8\; {\rm km \cdot h^{-1}} \times \frac{1000\; {\rm m}}{1\; {\rm km}} \times \frac{1\; {\rm h}}{3600\; {\rm s}} \\ &\approx 1.908\; {\rm m \cdot s^{-1}}\end{aligned}[/tex].

Initial kinetic energy ([tex]{\rm KE}[/tex]) of the vehicle:

[tex]\begin{aligned}\frac{1}{2}\, m \, v^{2}\end{aligned}[/tex].

When the vehicle is brought to a rest, the elastic potential energy ([tex]\text{EPE}[/tex]) stored in the spring would be:

[tex]\displaystyle \frac{1}{2}\, k\, x^{2}[/tex].

By the conservation of energy, if the friction between the vehicle and the ground is negligible, the initial [tex]\text{KE}[/tex] of the vehicle should be equal to the [tex]{\rm EPE}[/tex] of the vehicle. In other words:

[tex]\begin{aligned}\frac{1}{2}\, m \, v^{2} &= \frac{1}{2}\, k\, x^{2}\end{aligned}[/tex].

Rearrange this equation to find an expression for [tex]k[/tex], the spring constant:

[tex]\begin{aligned}k &= \frac{m\, v }{x^{2}}\end{aligned}[/tex].

Substitute in the given values [tex]m = 1508\; {\rm kg}[/tex], [tex]v \approx 1.908\; {\rm m\cdot s^{-1}}[/tex], and [tex]x = 6.87\; {\rm m}[/tex]:

[tex]\begin{aligned}k &= \frac{m\, v }{x^{2}} \\ &\approx \frac{1508\; {\rm kg} \times 1.908\; {\rm m\cdot s^{-1}}}{(6.87\; {\rm m})^{2}} \\ &\approx 1.79 \times 10^{5}\; {\rm kg \cdot m \cdot s^{-2} \cdot m^{-3}}\\ &\approx 1.79 \times 10^{5}\; {\rm N \cdot m^{-1}}\end{aligned}[/tex]

Objects 1 and 2
attract each other with
a electrostatic force
of 72.0 units. If the charge of Object
is one-third the
original value AND the charge of object 2 is doubled AND
the distance separating Objects 1 and 2 is doubled, then the
new electrostatic force will be
units.

Answers

Answer:

12 units

Explanation:

Original F = C q1q2/r^2    now change the parameters

  New F = C  1/3 q1  2 q2  / (2r)^2

              =  2/12  C q1q2/r^2    <=======the new force is 1/6 of original

1/6 * 72 = 12 units  

When an object in simple harmonic motion is at its maximum displacement, its____________ is also at a maximum.

Answers

When an object in simple harmonic motion is at its maximum displacement, its acceleration is also at a maximum.

Reason: The speed is zero when the simple harmonic motion is at its maximum displacement, however, the acceleration is the rate of change of velocity. The velocity reverses the direction at that point therefore its rate of change is maximum at that moment. thus the acceleration is at its maximum at this point

Hope that helps!

A planet's moon travels in an approximately circular orbit of radius 8.6 107 m with a period of 6 h 25 min. Calculate the mass of the planet from this information.

Answers

Answer:

m v^2 / R = G M m / R^2       gravitational attraction = centripetal force

M = v^2 R / G       solving for M

period = 6 h 25 min = (6 * 3600 + 25 * 60) sec = 23,100 sec = T

v = 2 pi R / T

M = 4 pi^2 R^3 / (G T^2)

M = 39.5 * (8.6E7)^3 / (6.67E-11 * 2.31E4^2)

M = 39.5 * 636 / (6.67 * 5.34) * 10^24

M = 7.05 * 10^26 kg

How does the amount of solar energy change as Earth orbits the sun

Answers

Explanation:

As the Earth orbits the Sun, the tilt causes one hemisphere and then the other to receive more direct sunlight and to have longer days. The total energy received each day at the top of the atmosphere depends on latitude

Answer:

She is right!

Have a good day/Night!

Explanation:

Rex

A wave has a period of n seconds. What is the frequency of this wave?

Answers

Answer:

n Hz

Explanation:

I think I'm Sry if it is wrong.

Which describe the image formed by the convex
mirror? Check all that apply.
-real
-virtual
-inverted
-upright
-smaller
-larger

Answers

Answer:

virtual, upright, smaller

Explanation:

yes

In this lab, you will need to be able to describe how multiple waves interact with each other. 1) This does not add too much mathematical complexity to the wave equation (Eq. 2), and 2) it allows us to develop a closer approximation of real-life situations as well (e. G. Interacting ripple patterns in a pond, music, atomic physics, etc. ). Here, you will explore the superposition of two waves, y1 and y2, where:

Answers

The superposition of waves due to their interaction can either produce a constructive or destructive interference.

What is wave superposition?

Wave superposition refers to the the interaction of two or more waves when their parts overlap.

Example of wave superposition is multiple waves travelling through a rope.

The superposition principle states that when two or more waves overlap in space, the resultant disturbance is equal to the algebraic sum of the individual disturbances.

Based on phase difference between two or more waves, the superposition if the waves can result in either constructive or destructive interference .

Therefore, the superposition of waves due to their interaction can either produce a constructive or destructive interference.

Learn more about superposition of waves at: https://brainly.com/question/16602771



Yellow light (600 nm) passes

through a diffraction grating. Its first

order (m = 1) maximum occurs at

an angle of 21. 2°. What is the slit

separation d?

[?] x 10-6 m

Hint: Just fill in the number that goes in [?]

Answers

Answer:

1.66 x 10^-6 m

Explanation:

A 1.10-kg block of wood sits at the edge of a table, 0.790 m above the floor. A 1.15×10−2-kg bullet moving horizontally with a speed of 700 m/s embeds itself within the block.

What horizontal distance does the block cover before hitting the ground?

Answers

Answer:

I think u missspelled something be cause the the sum would be a good 0.2927

*PIC PROVIDED*
A solid disk of mass (M) and radius (R) rolls without slipping with a linear speed of (v). Find the maximum vertical height (h) to which it can roll if it goes up an incline. Answer in terms of M, R, v, and g.

(I assume g is for gravity)

Answers

Answer:

1/2 M V^2 = M g H

Initial kinetic energy equals final potential energy

H = V^2 / (2 g)        satisfies given conditions

2) What did Rutherford discover in his experiment?
a) nucleus
b) electrons
c) neutrons

Answers

A) nucleus because some aims reflected off the gold foil proving that there was something bigger inside the atom hence discovering the nucleus

A planet has a mass 0.051 times the mass of Earth and a diameter of about 0.160 times the diameter of Earth. What is the acceleration of a body falling near the surface of this planet

Answers

Answer:

Gravity on planet is 2 times earth gravity

Explanation:

Grav force =  G m1 m2 / (r^2)     now change  m1 and r

                  = G .051m1  m2 / ( .16 r)^2

                    = .051 /.0256   G m1 m2 / r^2

.051 /.0256 = ~ 2

Estuaries are the place where rivers flow into the sea, and the freshwater they contain meets and mixes with salty seawater. question 2 options: true false

Answers

Answer:

true

Explanation:

i did the test

The measurement of cosmic distances was helped tremendously by the discovery, in the early part of the 20th century, that in Cepheid variable stars, the average luminosity was related to:

Answers

In the early 20th century, the average luminosity in Cepheid variable stars was related to: the period of time it takes to vary.

What is a cosmic distance?

A cosmic distance can be defined as an accurate and precise measurement of the distance to celestial or astronomical objects such as:

GalaxiesStarsMoonSun

In the early 20th century, a discoery of the average luminosity in Cepheid variable stars was related by astronomers to the period of time it takes to vary and this helped tremendously in the measurement of cosmic distances.

Read more on cosmic distance here: https://brainly.com/question/23428619

A 1,500kg boulder falls off a 120m tall cliff on a planet that has a surface gravitational field of magnitude 3. 6 N/kg. Assume that the planet has no atmosphere. How long does it take for the boulder to strike the ground?
Write your answer using two significant figures

Answers

Answer:

8.16 seconds, enjoy physics

A 1,500kg boulder falls off a 120m tall cliff on a planet that has a surface gravitational field of magnitude 3. 6 N/kg. Assume that the planet has no atmosphere, it would take 8.16 seconds for the boulder to strike the ground

What are the three equations of motion?

There are three equations of motion given by  Newton

The first equation is given as follows

v = u + at

the second equation is given as follows

S = ut + 1/2×a×t²

the third equation is given as follows

v² - u² = 2×a×s

Note that these equations are only valid for a uniform acceleration.

where u and v are the initial and final velocity respectively

S is the total distance covered by the object

a is the acceleration of the object

As given in the problem a 1,500kg boulder falls off a 120m tall cliff on a planet that has a surface gravitational field of magnitude 3. 6 N/kg. Assume that the planet has no atmosphere

S = 120m, the initial velocity of the boulder is zero

u = 0

g = 3.6 m/s²

S = ut + 1/2at²

u= 0m/s , a= 3.6 m/s² and t = ? seconds

120  = 0×t + 0.5×3.6×t²

t² = 120 /(3.6×0.5)

t² = 66.667

t = 8.16 seconds

Thus, it would take 8.16 seconds for the boulder to strike the ground

Learn more about equations of motion from here

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During which two moon phases would the amount of light reflected from the moon appear to be equal from Earth? Why does this occur at different times in a month? (AKS6a, DOK 3)

A.
The light reflected appears the same during the new moon and full moon phases because the sun, moon and Earth are aligned.

B.
The light reflected appears the same during the new moon and first quarter moon phases because the sun, moon and Earth are at the same angles.

C.
The light reflected appears the same during the full moon and third quarter moon phases because the sun, moon and Earth are at the same angles.

D.
The light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.

Answers

The moon phase shows that D. light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.

What is a moon phase?

It should be noted that the moon phase simply means the portion of the moon that we can see from the Earth.

In this case, the light reflected during the first quarter and third quarter moon phases appears equal because the sun, moon and Earth are at right angles.

Learn more about moon on:

https://brainly.com/question/398659

A +1.4 nC charge exerts a repulsive force of 20.0 mN on a second charge
which is located a distance of 2.2 m away from it. What is the magnitude
and sign of the second charge?

Answers

Answer:

+ .00769 C

Explanation:

Whoever 'katie' is , removed my previous, innocuous answer for some reason....

The force is repulsive , so the charge is also POSITIVE

f = k q1 q2 / r^2  

   k = Coulombs constant = 8.98755 x 10^9  kg m^3 . (s^2 C^2)

   q 1 = 1.4 x 10^-9 C     f = 20 x 10^-3  N

    r = 2.2 m       q2 = ?

Sub in the values to get q 2 = + .00769 C

An ideal gas, initially at a volume of 0.777778 L and pressure of 9 kPa, undergoes isothermal expansion until its volume is 7 L and its pressure is 1 kPa. Calculate the work done by the gas during this process. Answer in units of J.

Answers

For an ideal gas, initially at a volume of 0.777778 L,  the work done by the gas during this process is mathematically given as

w=15.380613

What is the work done by the gas during this process.?

Generally, the equation for the work done  is mathematically given as

W=p1v1invfvi

Therefore

v2=p1v1/p2

v2=9*1.0.77778/1

v2=7.00002

In conclusion

w=7.00002ln7/0.777778

w=15.380613

Read more about Work

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A sailor pulls a boat along a dock using a rope at an angle of 35. 0º with the horizontal. How much work does the sailor do if he exerts a force of 455 N on the rope and pulls the boat 9. 50 m?




Calculate the kinetic energy of a truck that has a mass of 1900 kg and is moving at 45 m/s.




Find the mass of a car that is traveling at a velocity of 75 m/s North. The car has 5,040,000 J of kinetic energy.





How fast is a ball rolling if it contains 108 J of kinetic energy and has a mass of 3. 5 kg?


At an accident science on a level road, investigators measure a car’s skid mark to be 85 m long. The accident occurred on a rainy day, the coefficient of friction was estimated to be 0. 25. What was the speed of the car when the driver slammed on and locked the brakes?




A new conveyor system at the local packaging plan will utilize a motor-powered mechanical arm to exert an average force of 980 N to push large crates a distance of 15 meters in 30 seconds. Determine the power output required of such a motor.




Josh and Jake are both helping to build a brick wall which is 6 meters in height. They each lay 350 bricks, but Josh finishes this task in 2 hours while Jake requires 5. 5 hours to complete his part. Who does more work, or do they both do the same amount? Who has more power? Explain.

please help me

Answers

Answer:

What work is done when a person pushes an 80 kg washing machine 12m across the floor. The force of friction between the washing machine and floor is 500 N.

A sailor pulls a boat along a dock using a rope at an angle of 60° with the horizontal. How much work does the sailor do if he exerts a force of 255 N on the rope and pulls the boat 4.0m?

Explanation:

1. Potential energy and a roller coaster. A 1000-kg roller coaster car moves from point A to B then C.


(a) What is the potential energy at B and C

relative to A?


(b) What is the change in potential energy

as it goes from B to C?


(c) What is the potential energy at B and C relative to point C?


(d) What is the change in potential energy as it goes from B to C?

Answers

Answer:(a) With our choice for the zero level for potential energy of the car-Earth system when the car is at point B ,

          U

B

=0

When the car is at point A, the potential energy of the car-Earth system is given by

          U

A

=mgy

where y is the vertical height above zero level. With 135ft=41.1m, this height is found as:

y=(41.1m)sin40.0

0

=26.4m

Thus,

U

A

=(1000kg)(9.80m/s

2

)(26.4m)=2.59∗10

5

J

The change in potential energy of the car-Earth system as the car moves from A to B is

U

B

−U

A

=0−2.59∗10

5

J=−2.59∗10

5

J

(b) With our choice of the zero configuration for the potential energy of the car-Earth system when the car is at point A, we have U

A

=0. The potential energy of the system when the car is at point B is given by U

B

=mgy, where y is the vertical distance of point B below point A. In part (a), we found the magnitude of this distance to be 26.5m. Because this distance is now below the zero reference level, it is a negative number.

Thus,

Is the equation balanced? Why or why not? 2 Zn + 2 HCl ----------> 2 H2 + 2 ZnCl2 SPS3.bGroup of answer choicesYes because the law of conservation of matter is being followed. The mass of the reactants is equal to the mass of the products.No because the law of conservation of energy is not followed. There are different amounts of energy in the reactants and products.Yes because the law of conservation of energy is followed. There are equal amounts of energy in the reactants and products.No because the law of conservation of mass is not being followed. The hydrogen and chlorine atoms have different numbers of atoms in the reactants and products.

Answers

The equation is not balance because the law of conservation of mass is not being followed.

Why the equation is not balanced?

The hydrogen and chlorine atoms have different numbers of atoms in the reactants and products which is not balance on both sides i.e. reactant and products.

So we can conclude that the equation is not balance because the law of conservation of mass is not being followed.

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A new rechargeable battery pack is available for products that use aa batteries. Which of the following best explains how the data files in the table can be used to send a targeted e-mail to only those customers who have purchased products that use aa batteries to let them know about the new accessory?.

Answers

Answer:

D

Explanation:

Use the products file to generate a list of product IDs that use AA batteries, then use the list of product IDs to search the purchases file to generate a list of customer IDs, then use the list of customer IDs to search the customers file to generate a list of e-mail addresses

343. W/M^2 of energy is emitted by the sun to the earth. How much actually reaches the earth's surface?

A. About one fourth

B. Almost all

C. About a third

D. About half

Answers

If 343 W/m² of energy is emitted by the sun to the earth, the quantity that reaches the earth is : ( D ) which is about half.

What is radiation?

Radiation is the energy exchange that does not require a material medium for propagation.This is the process in which the sun exchanges heat with the earth.

Analysis:

When heat is exchanged between two bodies, heat is either, absorbed, transmitted or reflected. In the the cloud, energy is reflected back to the sun since the clouds are translucent, it allows a part to reach the clouds.

In conclusion, About half of this energy gets to the earth.

Learn more about Energy exchange between earth and sun : brainly.com/question/1410640

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Answer:

The correct answer is A. About one fourth.planation:

Explain how sound waves are created and how they travel

Answers

Answer:

Sound is produced when an object vibrates, creating a pressure wave. This pressure wave causes particles in the surrounding medium (air, water, or solid) to have vibrational motion. As the particles vibrate, they move nearby particles, transmitting the sound further through the medium.

Explanation:

The Special Olympics started for athletes with which disability?

Answers

Answer:

intellectual disabilities

Founded in 1968 by Eunice Kennedy Shriver, Special Olympics provides people with intellectual disabilities continuing opportunities to realize their potential, develop physical fitness, demonstrate courage and experience joy and friendship.

Explanation:

is an ocean wave electromagnetic or mechanical

Answers

Answer:

mechanical

Explanation:

the energy is carried by water <3 hope this helped

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