What percentage of the earth's surface is covered in water

A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves

Len [333]

Answer:

the velocity in all the cases will be same.

Explanation:

given,

girl throws a stone from the bridge

air is friction less

we have to find from the given cases in which case the velocity of stone will be greatest.

According to Work energy theorem work done by the sum of all the force is equal to kinetic energy.

As the air is frictionless hence the speed depend upon the height from which the stone is thrown.

height in all the cases is same.

so, the velocity in all the cases will be same.

3 0

3 years ago

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Which of the following statements is TRUE?

KIM [24]

Hello there!

<span>Which of the following statements is TRUE?

Correct answer: </span>Light waves are electromagnetic waves and sound waves are mechanical waves.

5 0

4 years ago

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a wheel 0.35m in diameter rotates at 2200rpm. calculate its angular velocity in rad/s and its linear speed and acceleration of a

bazaltina [42]

Answer:

( Angular Velocity = ( About ) 230 rad / s,

( Linear Speed = ( About ) 40.25 m / s,

( Acceleration = ( About ) 9290 m / $s^2$

Explanation:

Here we want the angular velocity in radians per second, the linear velocity and acceleration.

The diameter = .35 meters, and thus we can conclude that the radius be half of that, or .175 meters. For part ( a ), or the calculation of the angular velocity, it is given that the diameter rotates at 2200 revolutions per minute - but we need to convert this into radians per second.

We can say that there are 2π radians for every minute, and for every minute there are 60 seconds. Therefore -

( a ) w = 2,200 rpm( 2π rads / rev )( 1 min / 60 sec )...

Hence, w = ( About ) 230 rad / s

_____

For this second part we can calculate the the linear velocity by multiplying the angular velocity ( omega ) by the radius r -

( b ) v = w( r ) - Substitute,

v = ( 230 rad / sec )( .175 m )...

v = ( About ) 40.25 m / s

_____

And for this last bit here, to find the acceleration we can simply take the angular velocity ( omega ) squared, by the radius r -

( c ) $a_{rad}$ = w^2( r ),

$a_{rad}$ = ( ( 230 rad / sec )^2 )( .175 m )...

$a_{rad}$ = ( About ) 9290 m / $s^2$

7 0

3 years ago

Use the drop-down menus to complete each sentence about the layers of the atmosphere. If the did not exist, Earth might be destr

ozzi

Answer:

If the mesosphere did not exist, Earth might be destroyed by chunks of rock from space.

The stratosphere is located 12 to 50 kilometers from Earth's surface.

Both the trophosphere and mesosphere get colder as altitude increases.

The ozone in the stratosphere protects people from ultraviolet (UV) radiation.

The thermosphere has the highest temperature of any layer in Earth's atmosphere.

Explanation:

Different layers of the atmosphere are;

Troposphere

It is the lowest layer of atmosphere that begins at ground level and extends upward to about 10 km. In this layer, all organisms live, weather occurs and most clouds appear. As altitude increases, the temperature decreases i.e., the layer gets colder.

Stratosphere

This layer is located at the top of the troposphere and extends up to about 50 km from Earth's surface. The ozone layer present in this layer absorbs high-energy ultraviolet (UV) light from the Sun. Here, the temperature rises with altitude. The passenger jets are usually fly in this layer.

Mesosphere

Above the stratosphere, the mesosphere extends upward to about 85 km from Earth's surface. The chunks of rock from space such as meteors burn upon entering the mesosphere and protect the Earth. In this layer, the temperature gets colder as altitude increases and so the coldest temperatures (about -90° C) in Earth's atmosphere are found at the top of this layer.

Thermosphere

This layer is located above the mesosphere and the air here is really very thin. The thermosphere absorbs high-energy X-rays and UV radiation from the Sun and as a result, its temperature increases to hundreds or thousands of degrees i.e., 1,500° C or higher. This layer extends up to 500 to 1,000 km from the ground. Many satellites orbit Earth within this layer.

Ionosphere

The ionosphere is actually an extension of the thermosphere and so it is not a distinct layer like the others. It is filled with charged particles produced from the ionization of molecules by high temperatures in the thermosphere caused by the high-energy radiation from the Sun. The phenomenon called auroras (Northern Lights and Southern Lights) occurs in this layer. The different regions of the ionosphere reflecting the radio waves back to Earth and make the long-distance radio communication possible.

4 0

3 years ago

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If a 10. m3 volume of air (acting as an ideal gas) is at a pressure of 760 mm and a temperature of 27 degrees Celsius is taken t

kow [346]

We know, the ideal gas equation,
P1V1 / T1 = P2V2 / T2

Here, P1 = 760 mm
V1 = 10 m3
T1 = 27 + 273 = 300 K

P2 = 400 mm Hg
T2 = -23 + 273 = 250 K

Substitute their values,
760*10 / 300 = 400 * V2 / 250
25.33 * 250 = 400 * V2
V2 = 6333.333/ 400
V2 = 15.83

In short, Your Answer would be approx. 15.83 m3

Hope this helps!

7 0

3 years ago