(b)Suggest with reasons,what must be added to the flask to keep the liquid hot.
____________________________________________________​​

Answers

Answer 1

(a) a thin layer of vacuum is provided between the two walls of flask, to minimise the heat loss by conduction , because for conduction medium (molecules) is required , but now medium is absent .

.(b) the two walls are silvered to minimise the heat loss by radiation , because a shiny surface is a bad absorber and bad emitter of radiation i.e. good reflector of heat , so prevents the heat exchange between content of flask and surrounding .

(c) the lid of flask is provided with a tight cork stopper to minimise the heat loss by convection , so that convection currents cannot go out .

(d) a plastic (or metal) case is provided with a flask , to protect the flask from physical damage

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Related Questions

A wave that can travel through empty space?


A. electromagnetic wave
B. mechanical wave
C. compressional wave
D. transverse wave

Answers

Answer: B. Mechanical Waves

Explanation:

B hope this helps (I can be wrong)

A boat traveling across a river has a resultant velocity of 10 km/h and travels 34 degrees with respect to the shore. A) What is the boats velocity in m/s?
B) What is the velocity of the river in m/s?

Answers

Answer:

a) 1.55 m/s

b) 2.3 m/s

Explanation:

We know that the boat travels across the river, if we define the river as the x-axis, then the velocity of the boat is only on the y-axis.

Then we can write the velocity of the boat in still water as:

S = (0, B)

Now, when the boat is on the river, the velocity of the boat will be equal to the velocity of the boat in still water plus the velocity of the river.

The velocity of the river is:

v = (R, 0).

Then the velocity of the boat in that river is:

V' = (0, B) + (R, 0) = (R, B)

Now, we know that the velocity of the boat is 10km/h, and it travels at an angle of 34° with respect to the shore.

We can use the Pythagoreans theorem to write the components of this velocity as:

x-axis component = 10km/h*cos(34°) = 8.29 km/h

y-axis component = 10km/h*sin(34°) =  5.59 km/h

Then the velocity of the boat can be written in components as:

velocity = ( 8.29 km/h,  5.59 km/h)

And we knew that the velocity of the boat was written as  (R, B)

Then we must have:

R = 8.29 km/h

B = 5.59 km/h

a) The speed of the boat in m/s:

We know that the speed of the boat is 5.59 km/h.

First, we know that:

1km = 1000m, then:

5.59 km/h = 5.59*(1000m)h = 5,590 m/h

And we know that:

1h = 3600s

Then we can write:

5,590 m/h = 5,590 m/(3600s) = 1.55 m/s

b) The speed of the river in m/s:

We know that the speed of the river is 8.29 km/h

Using the same reasoning as above, we can do the change of units as follows:

8.29 km/h = 8.29 (1000m)/(3600s) = 2.3 m/s

whats the result of rounding 52.8015 into five significant figures​

Answers

Answer:

52.802

Explanation:

"Significant figures" in Mathematics refer to the digits that give accuracy to the value of a measurement. There are specific rules when it comes to determining the significant figures. For example, all non-zero digits are considered significant and zeroes located in-between non-zero numbers are significant. In the number given above, the digit "0" is located between "8" and "1," therefore, it is significant. All the digits above are significant.

The problem is only asking for "five" significant figures. We can do this by counting from the left to the right. By this means, we know that the number will be rounded off to the nearest thousandths, which is "1." The number after 1 is 5, which means that 1 digit will be added to number 1, thus, making the digit into "2." The last digit (5) will then be removed.

Explanation:

five significant of 52.8015=52.801 ..

A student is leaving the lesson and walking to Maths at a speed of 1m/s. He notices that he is late for the lesson and speeds up to 3 m/s. It takes him 4 seconds to speed up. Calculate his acceleration.

Answers

Answer:

Acceleration = 0.5 m/s²

Explanation:

Given the following data;

Initial velocity, u = 1m/s

Final velocity, v = 3m/s

Time, t = 4 seconds

To find acceleration;

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.

Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;

[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]

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

Substituting into the equation, we have;

Acceleration = (3 - 1)/4

Acceleration = 2/4

Acceleration = 0.5 m/s²

Jackson throws a football 30 meters at a speed of 15 m/s. How long was the football in the air before Laurence caught it for touchdown

Answers

Answer:

2s

Explanation:

Given parameters:

Distance  = 30m

Speed  = 15m/s

Unknown:

Time before Laurence caught it = ?

Solution:

To solve this problem;

    Speed  = [tex]\frac{disance }{time}[/tex]  

 Time taken  = [tex]\frac{distance }{speed }[/tex]   = [tex]\frac{30}{15}[/tex]  = 2s

The time it takes is 2s

Given:

30 metersSpeed of 15 m/s

We will solve:

Speed  = [tex]\frac{distance}{time}[/tex]

Time taken  = [tex]\frac{distance}{time}[/tex] = [tex]\frac{30m}{15m/s}[/tex] = 2s

The time it takes is 2s

Body Systems Directly Involved (Give at Least 2)
Cartoon
13. Ouch! You step on a tack and jump away without even thinking. Then you decide to pick up the tack and place it back in a desk drawer.
I need the second one the nervous system and...

Answers

Answer:

Nervous system and immune system

Explanation:

The nervous system is involved because you immediately jumped away, that ur brain and nerves initiating the fight or flight response. The immune system is involved because the tack most likely pierced your skin, so your immune system needs to work to make sure the wound does not get infected.

How high did a worker lift a 25 kg bag of sand if it now has 2940 of gravitational potential energy

Answers

Answer:

12 m

Explanation:

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

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

Height (h) =?

Objects carried to a particular height will always experience an acceleration due to gravity of 9.8 m/s².

With the above in mind, we can obtain the height to which the load is lifted to as shown below:

Mass (m) of bag = 25 kg

Potential energy (PE) = 2940 J

Acceleration due to gravity (g) = 9.8 m/s².

Height (h) =?

PE = mgh

2940 = 25 × 9.8 × h

2940 = 245 × h

Divide both side by 245

h = 2940 / 245

h = 12 m

Therefore, the worker lifts the load to a height of 12 m.

Which of the following statements is TRUE concerning forces?
A. Forces in the same direction are added together
B. Forces in the opposite direction are subtracted from one another
C. An overall net force must be present in order for movement to occur
D. All of the above

Answers

The answer is d I took the test

In water, sound travels 1500 m/s. A whale sings at a frequency of 17 Hz. What will be the length of the sound wave?

Answers

Answer:

A 20 Hz sound wave is 75 m long in the water (1500/20 = 75) whereas a 20 Hz sound wave in air is only 17 m long (340/20 = 17) in air. As we descend below the surface of the sea, the speed of sound decreases with decreasing temperature.

A 5.00 kg crate is on a 21.0° hill.
Using X-Y axes tilted down the
plane, what is the y-component
of the weight?
(Unit = N)

Answers

Answer:

17.56 N

Explanation:

Given that,

Mass of a crate, m = 5 kg

It is on a 21.0° hill

We need to find the y component of the weight.

y component = mgsinθ

Put all the values,

y-component = 5×9.8×sin(21)

= 49×sin(21)

= 17.56 N

So, the y-component of the weight is 17.56 N.

Answer:

-45.745

Explanation:

it is negative because it is downwards.

Metals are good conductors of heat because .

Answers

Answer:

They have the highest melting point so that mean that the temperature and the are a conductive to electricity.

Explanation:

If a 1000 kg car is traveling at 3
meters per second, what is its
kinetic energy?

Answers

Kinetic energy:
KE= .5 mv^2
KE = .5 * 1000 kg * 3 m’s^2
KE = 4500 kg m^2/s^2
KE = 4500 Joules

Four velcro-lined air-hockey disks collide with each other in a perfectly
inelastic collision. The first disk has a mass of 50.0 g and a velocity of
0.80 m/s to the west, the second disk has a mass of 60.0 g and a velocity of
2.50 m/s to the north, the third disk has a mass of 100.0 g and a velocity of
0.20 m/s to the east, and the fourth disk has a mass of 40.0 g and a
velocity of 0.50 m/s to the south. What is the final velocity of the disks
after the collision?

Answers

Answer:

The magnitude of the final velocity is approximately 0.526 m/s in approximately the direction of 8.746° East of South

Explanation:

The given collision parameters are;

The kind of collision experienced by the four velcro-lined air-hockey disk = Inelastic collision

The mass of the first disk, m₁ = 50.0 g

The velocity of the first disk, v₁ = 0.80 m/s West = -0.8·i

The mass of the second disk, m₂ = 60.0 g

The velocity of the second disk, v₂ = 2.50 m/s North = 2.5·j

The mass of the third disk, m₃ = 100.0 g

The velocity of the third disk, v₃ = 0.20 m/s East = 0.20·i

The mass of the fourth disk, m₄ = 40.0 g

The velocity of the fourth disk, v₄ = 0.50 m/s South = -0.50·j

Therefore, the total initial momentum of the four velcro-lined air-hockey disk, [tex]\Sigma P_{initial}[/tex] is given as follows;

[tex]\Sigma P_{initial}[/tex] = m₁·v₁ + m₂·v₂ + m₃·v₃ + m₄·v₄ = 50.0×(-0.80·i) + 60.0×(2.50·j) + 100 × (0.20·i) + 40.0 × (-0.50·j)

∴ [tex]\Sigma P_{initial}[/tex] = -40·i + 150·j + 20·i - 20·j = -20·i + 130·j

∴ [tex]\Sigma P_{initial}[/tex] = -20·i + 130·j

By the law of conservation of linear momentum, we have;

[tex]\Sigma P_{initial} = \Sigma P _{final}[/tex] = -20·i + 130·j

Therefore, given that the collision is perfectly inelastic, the disks move as one after the collision and the four masses are added to form one mass, "m", m = m₁ + m₂ + m₃ + m₄ = 50.0 + 60.0 + 100.0 + 40.0 = 250.0

∴ m = 250.0 g

Let, "v" represent the final velocity of the four disks moving as one after the collision

We have;

[tex]\Sigma P _{final}[/tex] = m × v = 250.0 × v = -20·i + 130·j

∴ v = -20·i/250 + 130·j/250 = -0.08·i + 0.52·j

The final velocity of the four disks after collision, v = -0.08·i + 0.52·j

The magnitude of the final velocity, [tex]\left | v \right |[/tex] = √((-0.08)² + (0.52)²) ≈ 0.526

[tex]\left | v \right |[/tex] ≈ 0.526 m/s

The direction of the final velocity, θ = arctan(0.52/(-0.08)) ≈ -81.254°

The direction of the final velocity, θ ≈ -81.254° which is 8.746° East of South

IS IT B!! if not pls helpp!

Answers

Answer:

I believe you are correct but we just started this unit

Explanation:

A vertical spring with a force constant of 26 N/m has a relaxed length of 35 cm. A 200 g mass is then
attached to the end of the spring and is allowed to come to rest. (a) Find the length of the stretched spring.
(b) How much elastic potential energy is stored in the spring?

I just need the work please the answers is
(a) 45.2 J
(b) 0.0739

Answers

Answer:

(a) The length of the stretched string is approximately 42.53846 cm

(b) The elastic potential energy stored in the string is approximately 0.073877 Joules

Explanation:

(a) The given parameter are;

The force constant of the vertical spring, k = 26 N/m

The relaxed length of the spring, L = 35 cm = 0.35 m

The mass attached to the end of the spring, m = 200 g = 0.2 kg

By Hooke's law, we have;

F = k·x

Where;

F = The applied force on the sting = The weight of the attached mass, W

∴ F = W

The weight of the attached mass, W = m × g

Where;

g = The acceleration due to gravity ≈ 9.8 m/s²

Therefore, F = W = 0.2 kg × 9.8 m/s² = 1.96 N

From Hooke's law, we have;

x = F/k = 1.96 N/(26 N/m) ≈ 0.0753846 m

The extension of the stretched spring, x ≈ 0.0753846 m

The length of the stretched string, L[tex]_{stretched}[/tex] = L + x

∴ L[tex]_{stretched}[/tex] ≈ 0.35 m + 0.0753846 m ≈ 0.4253846 m

0.4253846 m = 42.53846 cm

The length of the stretched string ≈ 42.53846 cm

(b) The elastic potential energy stored in the string, U = 1/2·k·x²

By substituting the known values, we get;

U = 1/2 × 26 N/m × (0.0753849 m)² ≈ 0.073877 Joules

2. A uniform rod of weight 5N and length 1m is pivoted at a point 20cm from one of its ends. A weight is hung from the other end so that the rod balances horizontally. What is the value of the weight?

Answers

Answer:

The weight is 7.5 N

Explanation:

Since the rod is uniform, its weight applies downwards at its middle (i.e 50 cm mark). The diagram attached to this answer shows the appropriate sketch.

Applying the principle of moment to the question, let the weight by represented by W.

Total clockwise moment = Total counterclockwise moment

[tex]F_{1}[/tex] x [tex]d_{1}[/tex] = [tex]F_{2}[/tex] x [tex]d_{2}[/tex]

5 x 0.3 = W x 0.2

1.5 = 0.2 W

W = [tex]\frac{1.5}{0.2}[/tex]

   = 7.5 N

The value of the weight is 7.5 N.

The image shows landforms in Monument Valley, Utah.

Which correctly lists the three features shown in the photo?

folds, strike-slip faults, and anticlines
anticlines, synclines, and folds
synclines, normal faults, and strike-slip faults
normal faults, folds, and anticlines

Answers

The correctly lists the three features shown in the photo is folds, strike-slip faults, and anticlines.

What is the difference between folds and failures?

Modern folds are those that emerged recently (on the scale of geological periods), that is, in the Tertiary Period (between 65 million and 2.5 million years ago). Faults are geological structures that originate from vertical (top-down) or inclined internal forces.

The transcurrent fault – also called horizontal fault – occurs when there is displacement in the horizontal plane between the two blocks, being more common in zones where two tectonic plates meet, when these also move horizontally.

See more about transcurrent fault at brainly.com/question/2387953

#SPJ2

Answer: folds, strike-slip faults, and anticlines. (A)

Explanation: Got it right on my exam on Edge.

You blow up a balloon but don't tie it. When you let it go, it flies around the room.
Which of Newton's Laws does the scenario describe?
1st Law
2nd Law
3rd Law

Answers

Answer:

3rd law beacuse there a flies

Which type of matter is likely to absorb the most sound waves? A. Metal door B. Loudspeaker C. Hot air O D. Foam wall​

Answers

Answer:

its either A or D

Explanation:

They use foam walls in like asylums but in the movies all the bad guys say "They can't hear you the metal is too thick" so its either one of those, hope it helped

Sound absorbing foams are typically softer and more lightweight than their sound blocking counterparts. This open and flexible cell structure acts as a natural soundwave absorber and prevents noises from reverberating off hard surfaces like walls, floors and ceilings.

What are sound waves ?

"A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords."

What is sound ?

"Sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the reception of such waves and their perception by the brain."

What is noise ?

Sound is defined as vibrations that travel through air or another medium that can be heard when they reach a person's or animal's ears. Noise is defined as unwanted sound. In engineering, noise has the additional connotation of signals varying over time without meaning, whereas sound connotes meaningful signals.

Know more about sound wave here

https://brainly.com/question/11797560

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10 POINTS QUESTION: Why both are models for monomers, polymers, and cross-linked polymers

Answers

Answer:

Because both monomers and polymers and cross linked polymers are mers with physically properties which is good for applycations

Explanation:

because they are good for using and not using

also, this is a 5 point question, you are not  fooling anyone. thx for 5 points tho

A ball is thrown with 50J of kinetic energy, it hits a target which moves with 30J of kinetic energy, how much energy goes to the thermal store of the surroundings?

Answers

Answer:

The energy that will go will for thermal store of the surroundings is 20 J.

Explanation:

Given;

kinetic of the thrown ball, K.E₁ = 50 J

kinetic energy used to move the target, K.E₂ = 30 J

The excess energy that will go will for thermal store of the surroundings;

ΔK.E = K.E₁ - K.E₂

ΔK.E = 50J - 30J

ΔK.E = 20 J

Therefore, the energy that will go will for thermal store of the surroundings is 20 J.

A vector
of magnitude 5 units and another vector ū of magnitude 3 units point in directions
differing by 60°. Find out (a) the scalar product of the two vectors and (b) the vector product of the two vectors​

Answers

Answer:

7.5 units

13 units

Explanation:

[tex]|v|=5\ \text{units}[/tex]

[tex]|u|=3\ \text{units}[/tex]

[tex]\theta[/tex] = Angle between the vectors = [tex]60^{\circ}[/tex]

Scalar product is given by

[tex]u\cdot v=|u||v|\cos\theta\\ =3\cdot 5\cdot \cos60^{\circ}\\ =7.5\ \text{units}[/tex]

The scalar product of the vectors is 7.5 units.

Vector product is given by

[tex]u\times v=|u||v|\sin\theta\\ =3\times 5\sin60^{\circ}\\ =13\ \text{units}[/tex]

The vector product of the vectors is 13 units.

Guidewords for the word “serpent” may be
a.
Serbia and service
c.
Seltzer and Saturday
b.
Seattle and section
d.
Solitude and second
THE CORRECT ONE IS A!!!!!!!!

Answers

Answer:

A. Serbia and service

Explanation:

A guide word is a word written on top of a page to indicate the first or last word entry on that page. For example in a dictionary, they indicate the alphabetical first and last words on the page.

In this example; the word ' serpent ' note the first three letters to guide you in the words that are on that page;

In this case : Serbia  and Service.

4) Which is the BEST description of a tectonic plate? *
O A. Tectonic plates consist of the lithosphere and part of the asthenosphere.
O B.Tectonic plates are large pieces of mesosphere that never move.
C. Tectonic plates are large pieces of lithosphere that move on tope of the
asthenosphere.
O D. None of these answers is correct.

Answers

Using process of elimination the answer is D

Answer:

The answer is A

Explanation: i took k12

Henry designs an experiment to find out why plants without flowers tend to be wind-pollinated and not animal-pollinated. He takes samples from a variety of plants and studies them in the field. He finds that the evidence supports his hypothesis. Which of these was the hypothesis Henry was testing? Choose the correct answer. Nonflowering plants make less pollen than flowering plants. Nonflowering plants lack the structures to attract animal pollinators. Nonflowering plants grow close to the ground and capture fewer pollinators. Nonflowering plants grow close to the ground because they have no pollen grains.

Answers

Answer:

option 2

Explanation:

you are very welcom

Which of these would be the most efficient means to transmit light pulses over long distances?

Answers

Answer: It’s fiber optics so B

4. A toy car travels 60 m during 5.7 s at a constant speed. What is the speed of the toy car?
15.556
13.526
6.116
10.526
None of these is correct.

Answers

Answer: 10.526m/s

Explanation:

The speed of the toy car would be calculated as the distance travelled by the toy card divided by the time taken. This will be:

= Distance travelled / Time taken

= 60/5.7

= 10.526m/s

The speed of the toy car is 10.526 meters per second.

[04.04] Which best describes the current atomic theory? ​

Answers

Atoms are composed of electrons in different clouds around a positive nucleus.

Help Please! 5 questions for 25 points? seems fair? Thank you!

Answers

Answer:

1. where the skater turns and goes back in the opposite direction- point w

2. gravitational force of the object

3. point a

4. the bar representing sphere 4 should be twice as tall as the bar representing sphere 2

5. B; its mass is smaller (?)

yolo

Answer:

ABCDEFGHIJKLMNOPQRSTUVWXYZ

Explanation:

which wave carries the highest energy?​

Answers

Answer:

Gamma rays

Explanation:

The highest wave of energy is gamma ray.
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