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3 years ago

Why does your hand feel cool if you spill some alcohol on it?

2 answers:

6 0

<span>It takes heat to make something evaporate, so it takes heat from your arm. Alcohol easily evaporates at room temperature, so it feels cool. This is also why you feel cool when getting out of the pool. The water on your skin evaporates.

</span>

Evgesh-ka [11]3 years ago

6 0

The heat transfers from your warm hand to the alcohol. The energy leaving your hand causes it to “feel cold.”

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Was the Hubble Space Telescope an initial success (explain your answer in one or more sentences)?

jarptica [38.1K]

The initial curvature and other settings of the mirrors on the Hubble did not produce good images. Space shuttle missions replaced/corrected the mirrors to give clear images.

4 0

3 years ago

Assume that the pressure in a room remains constant at 1.01

Ray Of Light [21]

Answer:

Explanation:

Given

Pressure $P_1=1.01\times 10^5 Pa$

Volume of air $V=60 m^3$

Initial Temperature $T_1=289 K$

$T_2=302 K$

Initial moles is given by

$PV=nRT$

$n_1=\frac{P_1V_1}{RT_1}$

$n_1=\frac{1.01\times 10^5\times 60}{R\cdot 289}$

when some gas escape out

no of moles is equal to

$n_2=\frac{P_2\times V_2}{R\cdot T_2}$

$n_2=\frac{1.01\times 10^5\times 60}{R\cdot 302}$

remaining no of moles $=n_1-n_2$

$=\frac{1.01\times 10^5\times 60}{R\cdot 289}-\frac{1.01\times 10^5\times 60}{R\cdot 302}$

$=\frac{1.01\times 10^5\times 60}{R}(\frac{1}{289}-\frac{1}{302})$

Mass of air escape out

$=(n_1-n_2)\times M$

$=(\frac{1.01\times 10^5\times 60}{R}(\frac{1}{289}-\frac{1}{302}))\times 28$

$=25.272\times 10^3\ g$

$m=25.272\ kg$

7 0

4 years ago

I'm not really good on this type of stuff :(

navik [9.2K]

Okay let me walk you through this, a resistor resists right? its in the name. so you can guess that it would be 4th one down, because if you resist you don't stop, you just slow down. So you should definitely know current is energy, and since electrons is energy you know that current is the second one down. You already have two. Heres a good test taking strategy, the first one says "materials that do conduct electricity just not as well as conductors" so you know that something that conducts electricity well is a conductor, the third one down. now you have 3/5 and you haven't used any real knowledge. So now you are stuck between something that blocks electricity and something that is okay with it. Since you know a conductor does good, wouldnt a semi-conductor be the first one? since it is semi or partially a conductor. Then you are left with insulators to block them out. I hope I left a decent enough explanation. :)

5 0

4 years ago

The international Space Station (ISS) orbits the Earth once every 90 mins at an altitude of 409 km. How high would it have to be

Oksi-84 [34.3K]

It would have to be 36,719 Km high in order to be to be in geosynchronous orbit.

To find the answer, we need to know about the third law of Kepler.

<h3>What's the Kepler's third law?</h3>

It states that the square of the time period of orbiting planet or satellite is directly proportional to the cube of the radius of the orbit.
Mathematically, T²∝a³

<h3>What's the radius of geosynchronous orbit, if the time period and altitude of ISS are 90 minutes and 409 km respectively?</h3>

The time period of geosynchronous orbit is 24 hours or 1440 minutes.
As the Earth's radius is 6371 Km, so radius of the ISS orbit= 6371km + 409 km = 6780km.
If T1 and T2 are time period of geosynchronous orbit and ISS orbit respectively, a1 and a2 are radius of geosynchronous orbit and ISS orbit, as per third law of Kepler, (T1/T2)² = (a1/a2)³
a1= (T1/T2)⅔×a2

= (1440/90)⅔×6780

= 43,090 km

Altitude of geosynchronous orbit = 43,090 - 6371= 36,719 km

Thus, we can conclude that the altitude of geosynchronous orbit is 36,719km.

Learn more about the Kepler's third law here:

brainly.com/question/16705471

#SPJ4

6 0

2 years ago

What two factors determine how fast weathering occurs

Mashutka [201]

<span>The factors that determine how fast weathering occurs are the type of rock, type of soil, time it takes, and the climate.</span>

5 0

4 years ago