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3 years ago

The boundary between the crust and mantle is marked by a seismic-velocity discontinuity called

2 answers:

7 0

The boundary between the crust and mantle is marked by a seismic-velocity discontinuity is called Mohorovicic discontinuity.

Mohorovicic discontinuity was discovered by Andrija Mohorovicic in 1909 who was a Croatian seismologist. He realized that the velocity of a seismic wave is related to the material's density where it is moving through. He decoded that the acceleration of the seismic waves that are observed within outer shell of the earth is a compositional change. Thus, the acceleration should be caused by a material of higher density.

oksano4ka [1.4K]3 years ago

3 0

Mohorovicic discontinuity is your answer

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Suppose a miracle car has a 100% efficient engine and burns fuel having an energy content of 40 MJ/L. If the air resistance and

Stolb23 [73]

Answer:

Distance traveled in 1 liter = 40 km

Explanation:

Distance traveled = Energy / Opposing force = 40 x 10^6 J / 1000 N = 40000 m or 40 km

So, the car will moves to a distance of 40 km per liter under the opposing force of 1000 N…

3 0

3 years ago

What is radioactivity????

butalik [34]

Radioactivity is a nuclear phenomenon. It is the process of spontaneous emission of α (alpha particles) or β (beta particles) and γ (gamma particles ) radiations from the nucleus of atoms during their decay.

Uranium and radium are the two radioactive substances.

Explanation:

<h3>Hope it helps you!!</h3>

5 0

2 years ago

Using an unmanned rocket to visit the space station requires 85.2 trillion BTU of energy. The best fuel for the mission will hav

Illusion [34]

We shall convert all of the densities to lbs/gal, so the product of
BTU/lbs and lbs/gal gives us the basis of comparison, which was "ratio of energy to volume".
grams / ml x 1 lbs/454 grams → 1 lbs/ 454 ml
1 lbs/454 ml x 3785.41 ml/gal → 3785.41 lbs/454gal
Conversion of g/ml = 8.34 lbs/gal
Looking at each fuel:

Kerosene:
18,500 x (8.34 x 0.82) = 126,517 BTU/gal

Gasoline:
20,900 x (8.34 x 0.737) = 128,463 BTU/gal

Ethanol:
11,500 x (8.34 x 0.789) = 75,673 BTU/gal

Hydrogen:
61,000 x (8.34 x 0.071) = 36,120 BTU/gal

The best fuel in terms of energy to volume ratio is Gasoline.
Gallons required:
BTU needed / BTU per gallon
= 85.2 x 10⁹ / 128,463
= 6.6 x 10⁵ gallons

5 0

3 years ago

If the average pitcher is releasing the ball from a height of 1.8 m above the ground, and the pitcher's mound is 0.2 m higher th

mina [271]

The catcher can catch the ball at a height of 0.96 m from the ground.

The distance between the pitcher's mound and the catcher's box is about 60'6", which translates to 18.44 m. An average pitcher can pitch with speeds ranging from 88 mph to 97 mph, which is from 39.3 m/s to 43.4 m/s.

Assume the pitcher pitches a ball horizontally with a speed of 40 m/s. If the catcher catches the ball in a time t, then the ball travels a horizontal distance x of 18.44 m and at the same time falls through a height y.

The horizontal motion of the ball is uniform motion since no force acts on the ball ( assuming no air resistance) and hence the acceleration of the ball along the horizontal direction is zero.

Therefore,

$x=ut$

Calculate the time t by substituting 18.44 m for x and 40 m/s for u.

$t=\frac{x}{u} \\ =\frac{18.44 m}{40 m/s} \\ =0.461s$

The ball is acted upon by the earth's gravitational attraction and hence it accelerates downwards with an acceleration equal to the acceleration due to gravity g.

Since a horizontal projection is assumed, the ball has no component of velocity in the downward direction.

Therefore, for vertical motion, which is an accelerated motion, the distance y, the ball falls in the time t taken by it to reach the catcher's box is given by the equation,

$y=\frac{1}{2} gt^2$

Substitute 9.8 m/s² for g and 0.461 s for t.

$y=\frac{1}{2} gt^2\\ y=\frac{1}{2}(9.8 m/s^2)(0.461s)^2=1.04 m$

The pitcher releases the ball at a height of 1.8 m from a mound which is at a height of 0.2 m. Thus, the ball is released at a height of 2.0 m from the ground. It falls through a distance of 1.04 m in the time it takes to reach the catcher.

Therefore, the height at which the catcher needs to keep his glove so as to catch the ball is given by, $(2.0 m)-(1.04 m)=0.96 m$

The catcher needs to hold his glove at a height of <u>0,96 m from the ground.</u>

8 0

3 years ago

URGENTE ¿Cuál de los siguientes términos corresponde al concepto presión? * A. Es la fuerza perpendicular que ejerce un cuerpo s

melomori [17]

Answer:

Respuesta correcta, opción D: Es la fuerza que un cuerpo ejerce perpendicularmente sobre el área en la que actúa.

Explanation:

La definición de presión es la fuerza que un cuerpo ejerce en dirección perpendicular sobre el área en la que actúa.

Cuando se aplica una fuerza sobre la superficie de un cuerpo, la presión es la siguiente:

$P = \frac{F}{A}$

En donde:

F es la fuerza aplicada.

A es el área del cuerpo.

Por lo tanto la opción correcta es la D: es la fuerza que un cuerpo ejerce perpendicularmente sobre el área en la que actúa.

Espero que se sea de utilidad!

6 0

3 years ago