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3 years ago

A thermos bottle has two layers, a glass layer and a vacuum layer. The vacuum layer is the better _____.

1 answer:

6 0

The vacuum layer is the better insulator.
A thermos bottle like this has two walls made of glass and vacuum layer between those walls. Vacuum layer has very few molecules and they are distant from each other so heat transfer is prevented. That way liquid in thermos remain warm or cold.

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A steel ball is dropped from a building's roof and passes a window, taking 0.12 s to fall from the top to the bottom of the wind

Dvinal [7]

The top of the WINDOW is 19 meters from the ground. also steel balls dont bounce.

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4 years ago

A 480N sphere 40.0cm in radius rolls without slipping 1200cm down a ramp that is inclined at 53 0 with the horizontal. What is t

IgorC [24]

As we know that sphere roll without slipping so there is no loss of energy in this case

so here we can say that total energy is conserved

Initial Kinetic energy + initial potential energy = final kinetic energy + final potential energy

$\frac{1}{2}mv_i^2 + mgh = \frac{1}{2}mv^2 + \frac{1}{2}I\omega^2+ mgh'$

as we know that ball start from rest

$v_i = 0$

height of the ball initially is given as

$h = Lsin\theta$

$h = 1200sin53 = 960 cm$

also we know that

$I = \frac{2}{5}mR^2$

also for pure rolling

$v = r\omega$

also we know that

$480 = m*9.8$

$m = 49 kg$

now plug in all data in above equation

$480*9.60 + 0 = \frac{1}{2}*49*(0.40*\omega)^2 + \frac{1}{2}*\frac{2}{5}*49*(0.40)^2\omega^2 + 0$

$4608 = 3.92\omega^2 + 1.568\omega^2$

$\omega^2 = 839.65$

$\omega = 29 rad/s$

So speed at the bottom of the inclined plane will be 29 rad/s

7 0

4 years ago

a car dealer sells 4 makes of cars in 5 colors with either standard or automatic transmissions. how many variations does the dea

Anuta_ua [19.1K]

<u>The number of variations the dealership have is 40 cars</u>.

Data given;

The number of different product = 4
The number of transmission = 2 (standard or automatic)
The numbers of colors available = 5

<h3>Dealership variation </h3>

This is the total numbers of cars available in the dealer shop at the moment.

To get that, we simply multiply the numbers of colors available, the number of transmission and the makes of car available.

This is equal to

$4*2*5=40$

From the above calculation, we can say that <u>the variations the dealership offers is 40</u>

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Learn more on combination here

brainly.com/question/10339517

7 0

3 years ago

A claw hammer is used to pull a nail from a piece of wood. Where should you place your hand on the handle and where should the n

Alex Ar [27]

<span>You will exert less force the more the lever is longer. So, you need to place your hands as high as possible with the hammers handle.</span>

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4 years ago

Suppose a 350-g kookaburra (a large kingfisher bird) picks up a 75-g snake and raises it 2.5 m from the ground to a branch. (a)

mafiozo [28]

(a) The work done by the bird to raise the snake on the branch is equal to the product between the weight of the snake and the height of the branch above the ground:

$W_1 = mg h$

where $m=75 g=0.075 kg$ is the mass of the snake and $h=2.5 m$ is the height of the branch with respect to the ground. Substituting numbers into the equation, we find

$W_1 = (0.075 kg)(9.81 m/s^2)(2.5 m)=1.84 J$

(b) The work the bird did to raise its own centre of mass from the ground to the branch is equal to the product between the bird's weight and the height of the branch:

$W_2 = mgh$

where $m=350 g=0.35 kg$ is the mass of the bird. Substituting numbers into the equation, we find

$W_2 = (0.35 kg)(9.81 m/s^2)(2.5 m)=8.58 J$

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3 years ago