1. How are hot and cold packs constructed so that the reaction takes place only when needed?
2. Hypothesize two ways that you could change the amount of heat given off or absorbed in these packs.

Answers

Answer 1

Answer:

1.They are constructed of a large pouch containing a dry chemical plus an inner pouch of water. The hot/cold pack is activated by breaking the seal on the pouch of water and shaking the pack vigorously. This action mixes the water


Related Questions

Are women sports underpaid compared with man? (Example: Women's USA soccer team is paid way less then Men's USA soccer team)

DO NOT PUT LINKS!!

Answers

Answer:

Yeah of course

Explanation:

Its obvious because more people are attracted to men soccer

I would say yes and no at the same time whatever way you are looking at it . Cause in a article it says men’s viewer ship in 2018 soccer is 3.5 billion views on television compared to the woman’s which was 1.1 billion views . So the more views the woman’s and men’s soccer gets the more they get paid . In which in a way that’s sets the woman’s pay way lower compared to the men’s.

Please help me with this (20 points)

Answers

Answer:

1. troposphere

2. troposphere (still)

3. The most abundant gas in the atmosphere is nitrogen, with oxygen second. Argon, an inert gas, is the third most abundant gas in the atmosphere.

4.The stratosphere is where you'll find the very important ozone layer. The ozone layer helps protect us from ultraviolet radiation (UV) from the sun. In fact, the ozone layer absorbs most of the UV radiation the sun sends to us. Life as we know it wouldn't be possible without this layer of protection.

5. It contains the ozone, which protects Earth from the sun's radiation. Why aren't there many meteors in the troposphere? They burn up before they reach the troposphere.

Explanation:

1.The troposphere is the atmospheric layer closest to the planet and contains the largest percentage (around 80%) of the mass of the total atmosphere. Temperature and water vapor content in the troposphere decrease rapidly with altitude.

2.The layer closest to Earth's surface is the troposphere, reaching from about seven and 15 kilometers (five to 10 miles) from the surface. The troposphere is thickest at the equator, and much thinner at the North and South Poles.

3. Explained in the answer.

4. Explained in the answer.

5. Explained in the answer.

A music fan at a swimming pool is listening to a radio on a diving platform. The radio is playing a constant- frequency tone when this fellow, clutching his radio, jumps off. Describe the Doppler Effect heard by (a) a person left behind on the platform and (b) a person down below floating on a rubber raft. In each case, specify (1) whether the frequency is greater or smaller than the frequency produced by the radio, (2) whether the observed frequency is constant, and (3) how the observed frequency changes during the fall, if it does change. Give your reasoning.

Answers

Answer:

The Doppler Effect is given by the following relation;

[tex]f' = \left (\dfrac{v + v_0}{v - v_s} \right) \times f[/tex]

Where;

f' = The frequency the observer hears

f = Actual frequency of the wave

v = The velocity of the sound wave

[tex]v_o[/tex] = The velocity of the observer

[tex]v_s[/tex] = The velocity of the source

Where the observer is stationary, we have;

(i) When the source is moving in the direction of the observer

[tex]f' = \left (\dfrac{v }{v - v_s} \right) \times f[/tex]

(ii) When the source is receding from the observer, we have;

[tex]f' = \left (\dfrac{v }{v + v_s} \right) \times f[/tex]

Therefore;

(a) A person left behind on the platform

For a person left behind on the platform, we have that the radio source is receding, therefore, we have;

[tex]f' = \left (\dfrac{v }{v + v_s} \right) \times f[/tex]

(1) Given that (v + [tex]v_s[/tex]) > v, therefore, v < (v + [tex]v_s[/tex]), f' < f, the frequency heard by the person left on the platform, f', is smaller (lower) than the frequency produced by the radio

(2) The frequency is not constant as the speed of the source is increasing while it under the acceleration due to gravity

(3) During the fall, the speed of the source continuously increases under the effect of gravitational attraction and therefore the frequency heard by the person on the platform becomes progressively smaller

(b) A person down below floating on a rubber raft

For the the person down below on the rubber raft, the radio source is advancing

Therefore, the radio source is moving towards the person at rest down on the rubber raft, therefore, we have;

[tex]f' = \left (\dfrac{v }{v - v_s} \right) \times f[/tex]

(1) Given that (v - [tex]v_s[/tex]) < v, therefore, f' > f, the frequency heard by the person down below floating on the rubber raft, f', is greater (higher) than the frequency produced by the radio

(2) The frequency is not constant as the speed of the source is increasing while it under the acceleration due to gravity

(3) During the fall, the speed of the source continuously increases under the effect of gravitational attraction and therefore the frequency heard by the person on the platform becomes progressively greater (higher)

Explanation:

What will be the change of velocity of a 50kg object if a force of 2,000N
is applied to it for 0.010 seconds?

Answers

Answer:

0.4m/s

Explanation:

[tex]F = ma[/tex] where F= force, m= mass, and a=acceleration

we also know that,

a = Δv / t where Δv = change in velocity and t = time

thus F = m ( Δv / t)

[tex]2000=50(\frac{v}{0.01})[/tex]

[tex]\frac{2000}{5000} = v[/tex]

0.4m/s = Δv

Which of the following are devices that utilize electromagnets? Select all that apply?
relay switches
doorbells
crane pulleys
security locks

Answers

Doorbells and security locks!

An 80 kg runner has 3,000 J of kinetic energy. What is her velocity in m/s?

Answers

Answer: 8.6m/s

Explanation:From KE=1/2mv^2

In order to make v the subject of the formula we divide both sides by 1/2m. Thus V^2 will be left alone on the RHS. But we are looking for v and not v^2. Thus we find the square root of KE1/2m

Meaning V= sqrt[3000÷1/2 of 80]

=sqrt[3000÷40]

=sqrt(75)

=8.6m/s

Swampy areas can be found in many Florida locations. What weather conditions are most frequently found in this environment? *

Answers

Answer:

Heavy rain, extreme weather conditions, humid, water spouts, tornadoes, heavy lightening.

Explanation:

Swampy areas are a transition area formed where water and dry lands tend to meet. Swampy areas are actually forested areas with contains moist and humid weather conditions which has necessitated the wet soil around such an environment.

Florida is a very typical example of a weather that supports the creation of swampy areas due to its humid, heavy rains, water spouts,turnadoes etc and other extreme weather conditions.

An unbalanced force is at work when
A.
a book sits on a shelf.
B.
a piece of paper is on the floor.
C.
a model rocket takes off.
D.
a glass sits on a table.

Answers

I would go with C because all the rest of the answer are sitting on something.
ANSWER:(C) definitely when a model rocket takes off!!
,Thank you

Which law best describes contact force

A.
second law
B.
third law
C.
law of gravity
D.
first law

Answers

Answer:

b is the answer the third law

Explanation:

B because Newton's second law, which states that the force F acting on a body is equal to the mass m of the body multiplied by the acceleration a of its centre of mass, F = ma, is the basic equation of motion in classical mechanics.

kūna veikia 3N jėga kurios petys 20 cm. Koks jos momentas?​

Answers

Answer:

0.6Nm

Explanation:

Moment = Force * perpendicular distance

Given

Force = 3N

Distance = 20cm = 0.2m

Get te moment

Moment = 3 * 0.2N

Moment = 0.6Nm

Hence her moment is 0.6Nm

a balloon rubbed against denim gains a charge of -8.0 x 10^-6 c. What is the electric force between the balloon and the denim, which now has a charge of +8.0 × 10^-6 C, when the two are separated by a distance of 0.05 m?​

Answers

Answer:

230.4 N

Explanation:

Applying,

F = kqq'/r²..................... Equation 1

Where F = Electric force, k = Coulomb's constant, q = charge in the ballon, q' =  charge in the denium, r = distance between the charges.

From the question,

Given: q = -8.0×10⁻⁶ C, q' = +8.0×10⁻⁶ C, r = 0.05 m

Constant: k = 9×10⁹ Nm²/C²

Substitute these values into equation 1

F = (9×10⁹×8.0×10⁻⁶×8.0×10⁻⁶ )/0.05²

F = (576×10⁻³)/0.0025

F = 230.4 N.

At which angle do wires have to be to experience full force? What happens at other angles?

Answers

Answer:

The angle wires have to be placed to experience full force is such that the angle between the direction of current flow and the direction of the magnetic field is 90°

Explanation:

The direction of the force acting on a conductor through which a charge flows  is given by Flemings Left Hand Rule which states that the direction of the force acting on a conductor carrying a current of charge is perpendicular to both the direction in which the current is flowing and the direction of the magnetic field

Therefore, wires carrying flowing charges has to be placed such that the direction of charge (current) flow is perpendicular (at 90°) to an existing magnetic field to experience (maximum) full force

Which of the following is an example of a chemical reaction? A. mixing sugar and water B. melting wax c. tearing up a piece of paper D.burning paper

Answers

Answer:burning paper

Explanation: it’s burned, you can’t put it back together ( you can’t undo a chemical reaction/ change )

As a part of a laboratory investigation, Emily measured the volume of water in a graduated cylinder.Which of the choices correctly identifies the volume of water in the graduated cylinder?

Answers

Answer:

The choice that correctly identifies the volume of water in the graduated cylinder is option B i.e 35 mL

Explanation:

The complete question is

As a part of a laboratory investigation, Emily measured the volume of water in a graduated cylinder. Which of the choices correctly identifies the volume of water in the graduated cylinder? A. 38 mL B. 35 mL C. 37 mL D. 36.5 mL

The image for the question is attached herewith

Solution

The meniscus formed in this figure is a concave figure and in any concave figure the readings are taken from the bottom of the curve at eye level. In the attached image the bottom of the meniscus at the eye level is marked at 35 mL.

Hence the choice that correctly identifies the volume of water in the graduated cylinder is option B i.e 35 mL

When two different species compete for resources, it is______ competition.

Answers

Answer:

it is a interspecific competition

Explanation:

i just took a test with this question

Some people say it is rare to get HIV from a blood transfusion in the United States. True or false? Why?

Answers

Answer:

False

Explanation:

Because there is a 90% chance of contracting HIV from a blood transfusion

imagine no girls awnser this question ://

Answers

Answer:

im confused

Explanation:

wdym I am answering rn

The Sun creates energy through a series of steps known as:

Answers

The sun creates energy through nuclear fusion

The Sun creates energy through a series of steps known as nuclear fusion.

What is nuclear fusion?

Nuclear fusion is the process by which atomic nuclei combine to form heavier nuclei, releasing a tremendous amount of energy in the process. In the Sun, this process occurs in the core, where the temperature and pressure are high enough to overcome the electrostatic repulsion between positively charged atomic nuclei. Hydrogen atoms are fused together to form helium atoms, releasing energy in the form of light and heat.

The process of nuclear fusion in the Sun can be broken down into several steps.

The first step involves the collision of two hydrogen atoms to form a deuterium atom, releasing a positron and a neutrino in the process. The deuterium atom can then combine with another hydrogen atom to form helium-3, releasing a gamma ray. Finally, two helium-3 atoms can combine to form helium-4, releasing two protons and releasing even more energy in the process.

Therefore, the process of nuclear fusion in the Sun is a complex series of steps that releases a tremendous amount of energy and is responsible for the light and heat that we receive on Earth.

To learn about Kinetic energy click:

brainly.com/question/26472013

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State whether the following are true or false.
1. Sun dial and sand clock were used in ancient time. ______
2. Cubit, handspan and foot span are standard units of measurement. ______
3. Pendulum clock repeats its motion at equal intervals of time. ______
4. In digital clocks, mechanical vibrations are converted into digital electronic signals. ______
5. Sundials can also be used on rainy days.

Answers

Answer:

Explanation:

Start earning $78/hourly for working online from your home for few hours each day... Get regular payment on a weekly basis... All you need is a computer, internet connection and a little free time... Read more here... www.Nifty2.com

Una banda transportadora se utiliza para cargar canastos en un avión de carga, si µs = 0.5. ¿Cuál es el ángulo máximo de elevación para evitar el deslizamiento? Respuesta: 26.6

Answers

No se creo es 45.7 de nada

Which of the following methods transmits a drug directly into the bloodstream?

Answers

Answer:

I think Intravenous transmits a drug directly into the bloodstream.

Hope this help! :)

Sara travels east 6 miles and then goes south 3 miles and then north 8 miles. What is her displacement? Round
your answer to two significant figures.
a
Ob
6.3 miles SW
7.8 miles SW
0 miles
5.7 miles SW
7.8 miles NE
6.3 miles NE
od
Оe
Of
5.7 miles NE
Oh
9.1 miles sw
9.1 miles NE

Answers

Answer:

Explanation:

so her displacement is the distance from the start... she's now at a point (6,5) away from the start..  so what's the length of the side of the right triangle made by one side of 6 and the other of 5

Yes.. use Pythagoras theorem to solve this

C =  √([tex]6^{2}[/tex]+[tex]5^{2}[/tex])

C = √(36 + 25)

C = √61

C = 7.810  miles.. north east of where she started

C = 7.8 miles NE   :P

a student preformed a trick using a bar magnet and a paper clip. The paper clip was attached to a piece of string that was taped to the table. The clip appears to float just below the magnet. Explain how the floating paper clip trick works.

Answers

it works because the paper clip is heavier and more magnetic to the magnet

Please solve this worksheet for me It’s very important please don’t write unnecessary things or else I’ll report please help me i request

Answers

Answer:

1. 231.25 mL

2. 218.75 kPa

3. 6.21 L

4. 427.5 mL

5. 83.01 mL

6. 307.6 mL

7. 1.15 L

8. 440.4 mL

Explanation:

This questions describes Boyle's law. Using Boyle's law equation to solve the questions as follows:

P1V1 = P2V2

Where;

P1 = initial pressure

P2 = final pressure

V1 = initial volume

V2 = final volume

Please find the answers to each question as an attachment.

Explain the law of inertia in your own words.

Answers

A

An object at rest will remain at rest unless acted on by a force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by a force.

Explanation:

Answer:

Law of inertia is Newton's first law of motion..

Explanation:

It means that a body will tend to be in it's motion or tend to move in a straight line unless any external force is acted upon it..

Eg: while you are travelling in bus.. If breaks are suddenly applied your body falls forward because you were in motion with bus but it tries to be in motion when breaks are applied...

What heat transfer are uv rays from the sun. Radiation, conduction, or convection

Answers

Answer:

The ans is Radiation

Mark as brainliest !!

a metal rod has drawing pins stuck to it with wax and is heated at one end...

a)what do you think will happen in this experiment?explain your answer
b)how could this experiment be adapted to compare the codnucting properties of different materials?

Answers

The correct answer is b hun have a wonderful day
The answer is B
How could this experiment be adapted to compare the conducting properties of different materials?

11. A sensitive thermometer is one which
A. Is sensitive to heat
B. has large bore
C. can record big changes in temperature
D. can record small changes in temperature​

Answers

Answer:

A. ls sensitive to heat

this is correct answer

I hope it's helpful for you.......

A girl runs 40m due south in 40 seconds an d then 20m due north in 10 secondsCalculate.
the average speed,
her average velocity .
in her change in velocity for the whole journey!​

Answers

The average speed of the girl is 1.2 m/s.

Average velocity is defined as the trade in position or displacement (∆x) divided by the time durations (∆t) wherein the displacement takes place. The common velocity can be effective or negative depending upon the sign of the displacement. The SI unit of average velocity is meters per second (m/s or ms-1).

Given;

Total distance = 40 + 20 = 60 M

Displacement = 40 - 20 = 20 m south

total time = 40 + 10 = 50 seconds

Average speed =  total distance / total time

                          = 60/50

                          = 1.2 m/s

average velocity = total displacement / total time

                            = 20 / 50

                             = 0.4 m/s due south.

Average velocity is calculated by means of dividing your displacement (a vector pointing out of your initial role in your final position) through the entire time; the average pace is calculated by way of dividing the overall distance you traveled by means of the total time.

Learn more about average velocity here:-brainly.com/question/1844960

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what is the geologic time scale and how is it used​

Answers

Answer:

It is a type of map used to map out the geographical change over time. I believe

Explanation:

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