What does the half life for a radioactive material mean?

Answers

Answer 1
Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive

Related Questions

What is the velocity of the rock after 3.00 seconds (the rock is falling from a cliff)

Answers

Answer:

29.4 m/s

Explanation:

Using the formula: V=Vi + g.t

where V: final velocity, this is  what you want.

Vi: initial velocity, equals to zero as it is falling from rest.

g: acceleration due to gravity = 9.8

t: time, which equals 3 sec.

a cannon launches a 3.0 kg pumpkin with 110J of kinetic energy. what is the pumpkin’s speed?

Answers

Answer:

v = 8.56 [m/s]

Explanation:

The kinetic energy can be calculated by means of the following equation.

[tex]E_{k}=\frac{1}{2}*m*v^{2}[/tex]

where:

m = mass = 3 [kg]

v = velocity [m/s]

Ek = kinetic energy [J]

[tex]110 = \frac{1}{2} *3*(v^{2} )\\v^{2} = 220/3\\v=\sqrt{73.333}\\v=8.56[m/s][/tex]

What is the average speed of a toy car that travels 240cm in 1 minute?

Answers

4 cm/s is correct amañan and

Integrated Science- 8th grade science
Please Help ASAP!
Its almost the end of semester And I need to fix my grade for science so PLEASE help!
its almost report cards time!

Answers

Answer:

"Why"

Explanation: A scientific law is a description of how the natural world behaves under certain circumstances.

Answer:

technically its all of but the most  common is "Why"

Explanation:

On a sunny summer day, why does a white car with a light-colored interior stay cooler than a black car with a dark-colored interior?

Solar radiation reflects off the lighter colours, away from the car, thus keeping the car cool

Solar radiation is absorbed into the lighter colours, keeping the car cool

Solar radiation is absorbed into the darker colours, keeping the car cool

Solar radiation reflects off the darker colours, away from the car, thus keeping the car cool

Answers

Answer: Solar radiation reflects off the lighter colours, away from the car, thus keeping the car cool

Explanation: This is because lighter colors reflect a good amount of radiation while darker colors absorb it. Just like, Antarctica hasn't completely melted because it reflects a lot of the heat that is acting upon it. Or, you notice that you get hotter when you wear a black shirt opposed to a white one.

A person runs 3km north. One hour later, she runs 3km south, which of the following statements describes the persons complete trip

Answers

The person's complete trip was a 6km round trip because they traveled 3km north and then 3km south, returning to their original location.

What is trip?

A trip is a journey or excursion to some destination, usually for a specific purpose. It can be as short as a day trip or as long as a round-the-world adventure. A trip typically involves travel by foot, car, railroad, boat, or airplane and often involves multiple destinations. It may also involve activities such as camping, hiking, sightseeing, and other leisure activities. Travelers usually plan trips in advance to ensure they have enough time to see and do the things they want to. Trips can also be spontaneous, with travelers deciding on the fly where to go and what to do.

To learn more about trip
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Why is it possible to see yourself in an object that reflects light, but not in one that scatters light?

Answers

Reflection is when light bounces off an object. If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface. This is called specular reflection. ... Most of the things we see are because light from a source has reflected off it.

The normal force of a parked car is 15,000 Newtons. The coefficient of static friction between the rubber of the tires and the asphalt of the road is 0.75. What is the maximum static friction force?

Answers

Answer:

11250 N

Explanation:

From the question given above, the following data were obtained:

Normal force (R) = 15000 N

Coefficient of static friction (μ) = 0.75

Frictional force (F) =?

Friction and normal force are related by the following equation:

F = μR

Where:

F is the frictional force.

μ is the coefficient of static friction.

R is the normal force.

With the above formula, we can calculate the frictional force acting on the car as follow:

Normal force (R) = 15000 N

Coefficient of static friction (μ) = 0.75

Frictional force (F) =?

F = μR

F = 0.75 × 15000

F = 11250 N

Therefore, the frictional force acting on the car is 11250 N

If you drop a rock from 700 meters high, how long will it take the hit the ground?
(Remember to make height negative when solving because it is falling)
5
10
11.95
7.95

Answers

Answer:

The correct option is;

11.95

Explanation:

The given parameters are;

The height from which the rock is dropped = 700 meters

The time for the to hit the ground is given by the relation, h = u·t + 1/2·g·t²

Where;

h - The height = 700 meters

u = The initial velocity = 0

t = The time taken for the rock to cover the height, h, and hit the ground

g = The acceleration due to gravity = 9.81 m/s²

Therefore, we have by substitution,

700 = 0 × t + 1/2 × 9.81 × t²

∴ t = √(700/(1/2 × 9.81)) ≈ 11.95

The time for the rock to hit the ground, t ≈ 11.95 seconds.

In zoes egg experiment which two forces are balanced to keep it from hitting the pan

Answers

Answer:

The forces of push and pull

Explanation:

In the egg drop experiment, the egg is balanced on top of a toilet paper tube and balanced on a pan. The pan itself is placed on top of a glass of water. When the experimenter uses his hands to push the pan, the force of gravity pulls the egg downwards making it move down, right into the glass of water.

So the two forces which are applied in opposite directions are;

1. The force of push applied horizontally by the hand when it pushes the pan away, and

2. The force of pull caused by gravity which makes the egg move vertically downwards.

Answer:

Forces of push and pull

Margaret wants to go for a swim, and decides to jump in using the diving board that measures 3-m long.

She initially leaps with a velocity of 8.0 m/s at an angle of 80° to the horizontal.
What are the horizontal and vertical components of her velocity?

please help if you can!

Answers

Answer:

The horizontal component of her velocity is approximately 1.389 m/s

The vertical component of her velocity is approximately 7.878 m/s

Explanation:

The given question parameters are;

The initial velocity with which Margaret leaps, v = 8.0 m/s

The angle to the horizontal with which she jumps, θ = 80° to the horizontal

The horizontal component of her velocity, vₓ = v × cos(θ)

∴ vₓ = 8.0 × cos(80°) ≈ 1.389

The horizontal component of her velocity, vₓ ≈ 1.389 m/s

The vertical component of her velocity, [tex]v_y[/tex] = v × sin(θ)

∴ [tex]v_y[/tex] = 8.0 × sin(80°) ≈ 7.878

The vertical component of her velocity, [tex]v_y[/tex] ≈ 7.878 m/s.

What Critical Thinking Concepts and Skills will You Use Over the Holidays?

Answers

Answer:

I do not know, but I think I would use the scientific method and use my drawing skills to paint some nice Christmas things.

Explanation:

when it comes to graphs I am no genius lol​

Answers

Answer:

Option B

Explanation:

Displacement  = Area under the velocity-time graph

So to find the displacement of a particle from 7 to 8 seconds we take the triangle and calculate its area.

[tex]Area\ of\ a\ right\ angled\ triangle = \frac{1}{2}*(base)*(height) \\\\Area\ of\ a\ right\ angled\ triangle = \frac{1}{2}*(1)*(3) \\\\Area\ of\ a\ right\ angled\ triangle = 1.5[/tex]

So the displacement is 1.5 meters

I have an uploaded image so you can understand it better hope it helps

What force would be needed to increase a 450 kg object's velocity from 15 m/s to 75 m/s in 1 minute?

Answers

Answer:

450N

Explanation:

Given parameters:

Mass of object  = 450kg

Initial velocity  = 15m/s

Final velocity  = 75m/s

Time  = 1min  = 60s

Unknown:

Force applied  = ?

Solution:

To solve this problem, from Newton's second law of motion, we know that;

  Force  = mass x acceleration

  Acceleration  = [tex]\frac{v - u }{t}[/tex]

 v is the final velocity

 u is the initial velocity

 t is the time taken

Now;

    Force  = mass x  [tex]\frac{v - u }{t}[/tex]

   Force  = 450 x [tex]\frac{75 - 15}{60}[/tex]  = 450N

The gravitational force between two objects is
proportional to the products of the masses and
proportional to the square of the distance between them.

Answers

The complete question is;

The gravitational force between two objects is ______ proportional to the products of the masses and _______ proportional to the square of the distance between them.

Answer:

First dash is directly

Second dash is inversely

Explanation:

From Newton's law of gravitation the gravitational force is given by the equation;

F = GMm/r²

Where:

F is gravitational force

M and m are two masses representing the two objects

r is the distance between them

G = universal gravitational constant

Thus, if we are to write it in proportion format, we will have;

F ∝ Mm/r²

From this proportion relationship, we can see that the Gravitational force is directly proportional to the products of the two masses and inversely proportional to the square of the distance between them.

Answer:

DirectlyInversely

Explanation:

The gravitational force between two objects is directly  proportional to the products of the masses and  inversely proportional to the square of the distance between them.

define unit aland how many types of unit are there . Name them?​

Answers

Answer:

7. They arethe meter (m), the kilogram (kg), the second (s), the kelvin (K), the ampere (A), the mole (mol), and the candela (cd)

Explanation:

7. They arethe meter (m), the kilogram (kg), the second (s), the kelvin (K), the ampere (A), the mole (mol), and the candela (cd)

What training principle states that you must continue to exercise to mantain fitness a. Balance

Answers


The training principle that states you must continue to exercise to maintain fitness would be reversibility.

State the equation that links thinking distance, braking distance and stopping distance

Answers

Impulse, F = m • a or F = m • ∆v / t

NEED HELP ASAP question in picture

Answers

Answer:

B

Explanation:

I don't know how to break it down but I hope this is helpful!

Coretta feels confident in her abilities, and she frequently makes contributions to her local community. Based on this information, what can you assume is true about Coretta?

A She has good emotional health.
B She makes self-esteem a priority.
C She recently improved her mental health.
D She exercises at least twice a day.

Answers

I would say it’s probably A

Answer:

A She has good emotional health.

Explanation:

A teacher opens a window on a cold day. Which statement explains why the room starts to feel cooler? (1 point)
0 Air moves from the areas of higher temperature to areas of lower temperature
O Cold air is moving into the room from outside.
0 The density of the air is lower on the inside than on the outside
0 The kinetic energy of the air molecules outside is higher than the kinetic energy of the air molecules inside.​

Answers

Answer:

Air moves from the areas of higher temperature to areas of lower temperature.

Explanation:

this is because hotter temperatures seek out colder temps.

hope this helped!

When a teacher opens a window on a cold day. the room starts to feel cooler because air moves from the areas of higher temperature to areas of lower temperature.

What is convection of heat transfer?

The transfer of heat between two bodies by currents of moving gas or fluid is known as convective heat transfer. In free convection, air or water rises and is replaced by a cooler parcel of air or water as it moves away from the hot body.

As air moves from the areas of higher temperature to areas of lower temperature, when the teacher opens a window on a cold day, the air in the room moves out side and cold air takes the position inside the room. So, it feels cooler then.

To find more about convection, refer the link:

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Help me please help me it’s due today

Answers

I believe it’s parallel circuit. If one of the bulbs is removed then that bulb will be off but other bulb will remain lit.

But I’m case it’s series circuit then if one of the circuit is removed then all the bulbs will turn off because there is only one path for the current to flow

Answer:

Explanation:

A)  The function of a switch is to shut the circuit down. There is a current flow of zero. Press the switch again and the circuit works.

Answer: D

B) a. This is a parallel circuit. It is the way all house wiring works.

B) b. Nothing happens. The other two bulbs continue on as before until someone presses the switch.

Which two types of waves require matter in order to travel? A. Light waves B. Sound waves C. Electromagnetic waves D. Water waves​

Answers

Answer:

b & c

Explanation:

because is my choice

Which property of bromine could one predict based on the fact that it is a nonmetal in the halogen family?
A. It is highly reactive.
B. It is liquid at room temperature.
C. It is a good conductor of electricity.
D. It is a good conductor of heat.

Answers

Answer:its D

Explanation: but i think u meant to put not in the question but if u did mean to put not then its A

A 3900 kg truck is moving at 6.0 m/s what is the kinetic energy

Answers

Answer:

70200J

Explanation:

k.E = 1/2mv^2

K.E = 1/2(3900)(6)^2

Here you go, hope this helped

PLS HELP which ones would be made of cells? and which ones show cell walls?

Cork, Sponge, Wood, Plastic, Tree

Answers

The first question's answer depends on what you mean by "sponge". If you're talking about sea sponges, then all but plastic are made up of cells. Some sponges used for cleaning are also made of plant material but also other, non-organic materials like dyes.

Cell walls are only present in plant cells, so they would be found in cork (derived from a certain tree bark), wood, and trees. Synthetic sponges made with plant material might also contain them, but they wouldn't be made entirely of cells with walls.

From given options or choices all are made up of cells except plastic and among the other four Cork, Sponge, Wood, and tree all show cell walls except Sponge.

A cell is the basic structural unit of all living organisms and contains various cell organelles. On the base of different cell organelles or presence or absence of the certain organelles help in distinct and divide the cell type.

The major types of cells are:

Prokaryotic cellsEukaryotic cells

Plastic is not a living organism as there are no cells and is made up of polymers of hydrocarbon.

The cell wall is one of the major cellular structures that helps in identifying the type of cell organism and protects the organism from the external environment. It classifies the organism on its constituent of the cell wall.

In eukaryotic cells, animal cells have no cell wall, however, fungi cells, plant cells have a cell wall. A sponge is an animal and other cork wood, and trees are plants or plant-based products.

Thus, the sponge does not show the cell wall.

Learn more about the cell wall:

https://brainly.com/question/18662393

A baseball is thrown up into the air. What direction is the acceleration of the ball?

Answers

Answer:

Explanation: When you throw a ball up in the air, its direction/velocity on the way up, although it rises up into the air, is actually downward. On its way up, its speed decreases, until it momentarily stops at the very top of the ball s motion. Its acceleration is -9.8 m/s^2 at the very top.

Answer:

-9.8 m/s^v2

Explanation:

When you throw a ball up in the air, its direction/velocity on the way up, although it rises up into the air, is actually downward. On its way up, its speed decreases, until it momentarily stops at the very top of the ball s motion. Its acceleration is -9.8 m/s^2 at the very top.

which one?? please someone quick!​

Answers

Answer:

i think its second law of motion.

Explanation:

Answer:

it’s the second law

Explanation:

A cannonball with a perfect horizontal velocity of 50.0 m/s flies 350 m before hitting the
ground. How much time was the cannonball in the air? Remember t d/v
05s
O 10s
35 s
7s

Answers

Answer:

7 s

Explanation:

The time taken can be found by using the formula

[tex]t = \frac{d}{v} \\ [/tex]

d is the distance

v is the velocity

From the question we have

[tex]t = \frac{350}{50} = \frac{35}{5} = 7 \\ [/tex]

We have the final answer as

7 s

Hope this helps you

Who believe in astrology?

Answers

I don’t believe in that haha
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