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2 years ago

Pls help physics homework

Physics

2 answers:

Naddik [55]2 years ago

5 0

False

False

False

False

True

son4ous [18]2 years ago

3 0

False, false, false, false, true

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Relationship between oceanography and cryosphere

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<span>Oceanography is the study of the ocean and the cryosphere are the portions of the earth that are just frozen water (ice). When fresh water glaciers melt, they lower the salt levels in the ocean and and oceanographer studies that and makes sure that it wont have too much of an effect. The cryosphere plays a significant role in the global climate. </span>

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3 years ago

Give three examples of properties of elements

IgorC [24]

Answer: Atomic number, Atomic Mass, Ionic radius

Explanation:

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2 years ago

Read 2 more answers

find the time taken, if the speed of a train increased from 72 km/hr to 90 km/hr for 234 km. leave your answer in seconds

Airida [17]

Answer:

Time taken = 10400 s

Explanation:

Given:

Initial speed of the train, $u=72\textrm{ km/h}=72\times \frac{5}{18}=20\textrm{ m/s}$

Final speed of the train, $v=90\textrm{ km/h}=90\times \frac{5}{18}=25\textrm{ m/s}$

Displacement of the train, $S=234\textrm{ km}=234\times 1000=234000\textrm{ m}$

Using Newton's equation of motion,

$v - u = at\\a=\frac{v-u}{t}$

Now, using Newton's equation of motion for displacement,

$v^{2}-u^{2}=2aS$

Now, plug in the value of $a=\frac{v-u}{t}$ in the above equation. This gives,

$v^{2}-u^{2}=2\times \frac{v-u}{t}\times S\\(v+u)(v-u)=\frac{2(v-u)S}{t}\\t=\frac{2(v-u)S}{(v+u)(v-u)}\\t=\frac{2S}{v+u}$

Now, plug in 234000 m for $S$ , 25 m/s for $v$ and 20 m/s for $u$ . Solve for $t$ .

$t=\frac{2S}{v+u}\\t=\frac{2\times 234000}{25+20}\\t=\frac{468000}{45}=10400\textrm{ s}$

Therefore, the time taken by the train is 10400 s.

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3 years ago

\. A mixture of gases con-tains oxygen, nitrogen, and water vapor. What physical process could you use to remove the water vapor

Eddi Din [679]

Answer:

Condensation.

Explanation:

The boiling point of water is much higher than that of either nitrogen or oxygen gas . So when the mixture is condensed to a temperature lower than

100°C , water vapor will come out first in the form of water leaving other

elements of mixture in gaseous phase. In this way, water vapor will get separated from others.

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3 years ago

In which one(s) of the following situations will there be an INCREASE in Kinetic Energy? Group of answer choices A block slides

Maksim231197 [3]

Answer:

The Kinetic Energy INCREASE in the following situations:

a)A block slides down a frictionless incline:

e)A merry go round rotates faster due to the push by a person.

Explanation:

The energy kinetics is proportional to the square of the velocity:

$E_k=1/2*mv^2$

We study the cases:

a)A block slides down a frictionless incline:

The gravity made a positive work and the box get a extra velocity, then the kinetics energy INCREASE

b)A box is pulled across a rough floor at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

c)A stone at the end of a string is whirled in a horizontal circle at constant speed:

The magnitude of the velocity does not change, so the kinetics energy does not change as well

d)A projectile approaches its maximum height:

If the projectile approaches its maximum height, its velocity approaches to zero. Then the kinetics Energy DECREASE

e)A merry go round rotates faster due to the push by a person.

Thanks to the push, the magnitude of the velocity INCREASE, so the kinetics energy INCREASE as well

6 0

3 years ago