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3 years ago

How does a vacuum flask keep drinks hot? Explain in terms of conduction, convection and radiation.

1 answer:

4 0

Vacum flask has inner layer of glass and outer body of plastic.the glass has a reflective metal layer..when a hot drink is poured into the flask it prevents conduction.tight lid stops the convection.when radiation tries to leave the hot drink the reflective layer of the glass reflects it back so no heat can escape.

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While at the county fair, you decide to ride the Ferris wheel. Having eaten too many candy apples and elephant ears, you find th

Lorico [155]

Answer:

a = 0.701 m / s²

Explanation:

As the game is spinning the acceleration is centripetal

a = v² /r

The park system after a small period of acceleration goes at a constant speed, for which we can use the relations of the uniform motion

v = d / t

the distance of a circle is

d = 2π r

we substitute

a = (2π r / t) ² / r

a = 4 pi² r / t²

let's calculate

a = 4 pi² 12 / 26²

a = 0.701 m / s²

4 0

2 years ago

College students living off-campus frequently consume large amounts of ramen noodles and boxed macaroni and cheese. When they fi

tigry1 [53]

Answer:

Ramen Noodles and boxed Macaroni and Cheese are COMPLEMENTARY Goods

Explanation:

Complementary Goods are goods that are demanded jointly (together) to satisfy a particular want.

Ramen Noodles, Boxed Macaroni, Cheese are demanded together by off campus college students. So, they are complementary goods.

Also, their demand are directly related - demand of one good increases, demand of other good increases & demand of one good decreases , demand of other good decreases ; because they are demanded together.

After school end , consumption of all goods declining together - is also their characteristic pointing towards them being Complementary Goods .

4 0

3 years ago

A wave has a frequency of 15,500 Hz and a wavelength of 0.20 m. What is the

Hoochie [10]

Answer:

3100 m/s

Explanation:

The relationship between frequency and wavelength of a wave is given by the wave equation:

$v=f\lambda$

where

v is the speed of the wave

f is its frequency

$\lambda$ is the wavelength

For the wave in this problem,

f = 15,500 Hz

$\lambda=0.20 m$

Therefore, the wave speed is

$v=(15500)(0.20)=3100 m/s$

4 0

2 years ago

Exactly one turn of a flexible rope with mass m is wrapped around a uniform cylinder with mass M and radius R.

Dennis_Churaev [7]

Answer:

$\omega=\sqrt{\omega_0^2(\frac{M+m}{M})}$

Explanation:

The rotational kinetic energy when the cylinder is with the rope is:

$E_k=\frac{1}{2}I_c\omega_0^2+\frac{1}{2}I_r\omega_0^2$

where we used the fact that both rope and cylinder hast the same w. This E_k must conserve, that is, E_k must equal E_k when the rope leaves the cylinder. Hence, the final w is given by:

$E_{k1}=E_{k2}\\\\\frac{1}{2}I_c\omega_0^2+\frac{1}{2}I_r\omega_0^{2}=\frac{1}{2}I_c\omega^2\\\\\omega=\sqrt{\omega_0^2(\frac{I_c+I_r}{I_c})}$ (1)