Oceanic crust is much denser than continental crust

The picture shows an orange falling from an orange tree

Alinara [238K]

Answer:

A but not 100% certain.

Explanation:

you can eliminate C since it doesn't mention gravity, and B says gravity is pushing up on the orange. I think it is A because friction is going against the orange because it has to pass through the air, and that creates friction. I think that is the reason why things burn up when they enter the earths atmosphere.

6 0

3 years ago

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In the amusement park ride known as Magic Mountain Superman, powerful magnets accelerate a car and its riders from rest to 43.4

Anton [14]

Answer:

Average net force, F = 15157.15 N

Explanation:

It is given that,

The mass of the car and riders is, $m=3\times 10^3\ kg$

Initial speed of the car, u = 0

Final speed of the car, v = 43.4 m/s

Time, t = 8.59 seconds

We need to find the average net force exerted on the car and riders by the magnets. It can be calculated using second law of motion as :

F = m a

$F=m(\dfrac{v-u}{t})$

$F=3\times 10^3\ kg\times (\dfrac{43.4\ m/s-0}{8.59\ s})$

F = 15157.15 N

So, the average net force exerted on the car and riders by the magnets. Hence, this is the required solution.

5 0

3 years ago

The Hoover dam is a hydroelectric power plant that converts the energy of falling water into electricity. Which of the following

vlabodo [156]

The correct answer to the question is : B) The weight of the water, and C) The height of the water.

EXPLANATION :

Before coming into any conclusion, first we have to understand potential energy of a body.

The potential energy of a body due to its position from ground is known as gravitational potential energy.

The gravitational potential energy is calculated as -

Potential energy P.E = mgh

Here, m is the mass of the body, and g is the acceleration due to gravity.

h stands for the height of the body from the ground.

We know that weight of a body is equal to the product of mass with acceleration due to gravity.

Hence, weight W = mg

Hence, potential energy is written as P.E = weight × height.

Hence, potential energy depends on the weight and height of the water.

3 0

4 years ago

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What wavelength of light contains enough energy in a single photon to ionize a hydrogen atom?

BaLLatris [955]

There's probably a much quicker, easier way to do it, but I don't work with this stuff every day so this is the way I have to do it:

First, I searched the "ionization energy" of Hydrogen on Floogle. That's how much work it takes to rip the one electron away from its Hydrogen atom, and it's 13.6 eV (electron-volts).

In order to find the frequency/wavelength of a photon with that energy, I need the energy in units of Joules.

1 eV = 1.602 x 10⁻¹⁹ Joule (also from Floogle)

13.6 eV = 2.179 x 10⁻¹⁸ Joule

OK. Now we can use the popular well-known formula for the energy of a photon:

Energy = h · (frequency)

or Energy = h · (light speed/wavelength)

' h ' is Max Planck's konstant ... 6.626 × 10⁻³⁴ m²-kg / s

Wow ! The only thing we don't know in this equation is the wavelength, which is what we need to find. That's gonna be a piece-o'-cake now, because we know the energy, we know ' h ', and we know the speed of light.

Wavelength = h · c / energy

Wavelength =

(6.626 x 10⁻³⁴ m²-kg/sec) · (3 x 10⁸ m/s) / (2.179 x 10⁻¹⁸ joule)

<em>Wavelength = 9.117 x 10⁻⁸ meter </em>

That's 91.1 nanometers .

It's not visible light (visible is between about 390 to 780 nm), but it's not as short as I was expecting. I thought it was going to be an X-ray, but it's not that short. X-rays are defined as 0.1 to 10 nanometers. This result is in the short end of Ultra-violet.

(You have no idea how happy I am with this result. I figured it out exactly the way I showed you, and I never peeked. Then, AFTER I had my solution, I went to Floogle and searched to see what it really is, and whether I came out anywhere close. I found it in the article on the "Lyman Series". It says the wavelength of the energy released by an electron that falls in from infinity and settles in the n=1 energy level of Hydrogen is 91.175 nm ! This gives me a big hoo-hah for the day, and I'm going to bed now.)

6 0

3 years ago

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A salt shaker sits 0.102 m from

Ivahew [28]

The maximum speed is 0.55 m/s

Explanation:

For an object in uniform circular motion, the force of friction between the object and the ground provides the centripetal force required to keep the body in motion. Therefore we can write:

$\mu_s mg = m\frac{v^2}{r}$