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3 years ago

A thermos bottle has two layers, a glass layer and a vacuum layer.

Physics

1 answer:

SIZIF [17.4K]3 years ago

4 0

The vacuum layer is the better thermal insulator

Explanation:

Depending on how they conduct heat, materials can be classified into two types:

Thermal conductos: these are materials that are able to transfer heat efficiently. Examples of thermal conductors are metals in general: in fact, when you heat one side of a metal bar, the other end becomes hot very fast; this means that the heat has been transferred very quickly across the metal rod
Thermal insulators: these are materials that do not transfer heat well. In general, gases or rarefied substances are better insulators, because the particles are more spread apart, and therefore the heat (which is transferred by conduction through collisions between molecules) is transferred less efficiently, due to the large distance between the particles.

In this sense, vacuum is the best possible insulator. This is because vacuum contains no particles at all, so there cannot be transfer of heat by conduction (because there cannot be collisions between molecules), and therefore, vacuum is the best thermal insulator.

Learn more about heat:

brainly.com/question/3032746

brainly.com/question/4759369

#LearnwithBrainly

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Which has the greater acceleration, a person going from 0 m/s to 10 m/s in 10 seconds or an ant going from 0 m/s to 0.25 m/s in

monitta

Person-1

Initial velocity=u=0m/s
Final velocity=v=10m/s
Time=10s=t

$\\ \sf\longmapsto Acceleration=\dfrac{v-u}{t}$

$\\ \sf\longmapsto Acceleration=\dfrac{10-0}{10}$

$\\ \sf\longmapsto Acceleration=\dfrac{10}{10}$

$\\ \sf\longmapsto Acceleration=1m/s^2$

Person-2

initial velocity=0m/s=u
Final velocity=v=0.25m/s
Time=t=2s

$\\ \sf\longmapsto Acceleration=\dfrac{0.25-0}{2}$

$\\ \sf\longmapsto Acceleration=\dfrac{0.25}{2}$

$\\ \sf\longmapsto Acceleration=0.125m/s^2$

Person-1 is accelerating faster.

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3 years ago

A 1250 kg car is pulling a 325 kb trailer. The car and trailer have an acceleration of 2,15m/sec2 together. Determine the net fo

xenn [34]

To solve this problem we will apply the definition of Newton's second law, which says that force is equivalent to body mass by acceleration. In this case the mass of the trailer is 325Kg and its acceleration is $2.15m / s ^ 2$ , so we will proceed to replace and multiply these values to find the net force on this object.

$F= ma$

$F= (325 kg)(2.15 m/s^2)$

F= 698.75N

Under the reference system in which the direction of travel is the positive direction, the direction of the force will be positive.

7 0

3 years ago

What law describes light

Darina [25.2K]

The law of reflection

6 0

3 years ago

A ball rolls across a floor with an acceleration of 0.100 m/s2 in a direction opposite to its velocity. The ball has a velocity

Westkost [7]

Answer:

4.15 m/s

Explanation:

Its given that acceleration is 0.1 m/s² with a direction opposite to the velocity. Since, the direction of acceleration is opposite to the velocity, this gives us a hint that the velocity is decreasing and so acceleration would be negative.

i.e.

acceleration = a = - 0.1 m/s²

Distance covered = S = 6m

Velocity after covering 6 meters = Final velocity = $v_{f}$ = 4 m/s

We need to find the initial speed, which will be the same as the magnitude of initial velocity.

Initial velocity = $v_{i}$ = ?

3rd equation of motion relates the acceleration, distance, final velocity and initial velocity as:

$2aS = (v_{f})^{2}-(v_{i})^{2}$

Using the known values in the formula, we get:

$2(-0.1)(6)=(4)^{2}- (v_{i})^{2}\\\\ (v_{i})^{2}=16+1.2\\\\ (v_{i})^{2}=17.2\\\\ v_{i}=4.15$

Thus, the initial speed of the ball was 4.15 m/s

3 0

4 years ago

A weight suspended from a spring is seen to bob up and down over a total distance of 20 centimeters twice each second.

Zielflug [23.3K]

Answer

8. 2 Hz

9. 0.5 seconds

10. 20 cm

Explanation

Q 8

Frequency is the number of oscillation in a unit time. It is the rate at which something repeats itself in a second.

In this case, the spring bob up and down 2 times per second.

∴ Frequency = 2 Hz

Q 9

Period is the time taken to complete one oscillation.

2 oscillations takes 1 second

1 oscillation = 1/2 seconds.

∴ Period = 0.5 seconds

Q 10

Amplitude is the the maximum displacement of the spring.

In this case the spring bob up 20 cm. This is it's displacement.

∴ Amplitude = 20 cm

5 0

3 years ago