can you help me answer these two please


2.How did astronomers figure out that the earth is round

Answer:

5 m/s

Explanation:

Given that,

A vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west​.

It is assumed to find the resultant velocity of the vehicle. Let east side is positive and west is negative. So,

[tex]v=v_1+v_2\\\\=20+(-15)\\\\=5\ m/s[/tex]

Hence, the resultant velocity of the vehicle is equal to 5 m/s.

Answer:

A. Moon

Explanation:

The Moon is hundreds of thousands of miles away from the Earth while the other options are hundreds of millions of miles away.

Respuesta:

2 × 10⁴ V

Explicación:

Paso 1: Información provista

Paso 2: Convertir q a Coulomb

Usaremos el factor de conversión 1 C = 10⁹ nC.

4 nC × 1 C/10⁹ nC = 4 × 10⁻⁹ C

Paso 3: Calcular el potencial eléctrico (V) de la esfera

Usaremos la siguiente fórmula.

V = W/q

V = 7 × 10⁻⁵ J/4 × 10⁻⁹ C = 2 × 10⁴ V

Answer:

The Earth spins on its axis once a day.

Explanation:

In simple words,The Earth revolves on its axis once every 24 hours and circles the sun once every 365 days. The Earth's rotation on its axis, not its orbit throughout the sun causes day as well as night. The word 'one day' refers to the period it requires the Earth to spin entirely on its axis, which involves both day as well as night.

Answer:

The magnitude of the impulse is 1.4 Ns in the West direction.

Explanation:

The impulse equation is given by:

[tex]\Delta p=m\Delta v[/tex]

Where:

So we will have:

[tex]\Delta p=0.140(25-15)[/tex]

[tex]\Delta p=1.4\: Ns[/tex]

Therefore, the magnitude of the impulse is 1.4 Ns in the West direction.

I hope it helps you!

Answer:

They speed up as temperature increases.

Explanation:

As temperatures increases within a molecule the particles will speed up.

Answer:

the answer would depend on the motion if the surface

Answer:

Mined materials are needed to construct roads and hospitals, to build automobiles and houses, to make computers and satellites, to generate electricity, and to provide the many other goods and services that consumers enjoy.

Explanation:

The reason why motors are designed so that the polarity of the electromagnet constantly flips.is

C. so the electromagnet will continuously turn

The reason motors are designed so that the polarity of the electromagnet constantly flips is to continuously turn the electromagnet. This allows the motor to rotate continuously, rather than becoming stuck in one position.

The flipping of the polarity causes the electromagnet to attract and repel from the permanent magnets, creating a rotating motion.

Therefore, the correct answer is C.

Learn more about motors at:

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#SPJ1

Answer:

600 J

Explanation:

KE = 1/2 mv^2

Answer:

If I was the white mouse, I would either find somewhere to hide that matches my fur color to camoflouge with or dig into the dirt so less visible.

To find white colour habitat.

If I was the white mouse, I would find white colour place for living because in that white colour the predators can't see me and i will be safe from them so we can conclude that finding white colour habitat is the best choice to safe myself.

Learn more about survive here: https://brainly.com/question/24323334

Answer:

Beach ball 4

Explanation:

it is because, Potential Energy = M G H

P(e) directly proportional to H.

if H increase then P energy also increases

Answer:

Yes, its true

Explanation:

hdheheishdhieijzuwhs

Answer: yes its true

Explanation:

nmo

Answer:

b

Explanation:

Answer:

the ball's was lowered because of the gravitational force and because of the friction force's

Answer:

modern world

Explanation:

Answer: [tex]0.708\ mA[/tex]

Explanation:

Given

[tex]E_o=20\ V/m[/tex]

[tex]\omega =10^7\ s^{-1}[/tex]

Cross-sectional area [tex]A=0.40\ m^2[/tex]

Current density is given by

[tex]J=\epsilon_o \dfrac{dE}{dt}[/tex]

Displacement current

[tex]\Rightarrow I=JA\\\Rightarrow I=8.854\times 10^{-12}\times 20\times 10^7\times 0.4\\\Rightarrow I=0.708\times 10^{-3}\ A[/tex]

The required value of the maximum displacement current of the given space is  [tex]7.08 \times 10^{-4} \;\rm A[/tex].

Given data:

The intensity of electric field is, [tex]E_{0}=20 \;\rm V/m[/tex].

The angular frequency of electric field is, [tex]\omega=1.0 \times 10^{7} \;\rm s^{-1}[/tex].

The cross-sectional area of space is, [tex]A =0.40 \;\rm m^{2}[/tex].

In the given problem, the instantaneous electric field is given by [tex]E = E_{0} \times cos(\omega t)[/tex]

So, the expression for the current density is,

[tex]J= \epsilon_{0} \times \dfrac{dE}{dt}[/tex]

Here, [tex]\epsilon_{0}[/tex]  is the permittivity of free space. Solving as,

[tex]J= \epsilon_{0} \times \dfrac{d(E_{0} \times cos(\omega t))}{dt}\\\\J= -\epsilon_{0} \times E_{0} \times \omega \times sin(\omega t)[/tex]

And the expression for the maximum displacement current is,

[tex]I = J \times A[/tex]

And the maximum displacement current is possible only when, J is positive and J will be positive for  [tex]sin(\omega t)=-1[/tex].

Then solving as,

[tex]I = (-\epsilon_{0} \times E_{0} \times \omega \times sin(\omega t)) \times A\\\\I = (-8.85 \times 10^{-12} \times 20 \times (1.0 \times 10^{7}) \times (-1)) \times 0.40\\\\I = 7.08 \times 10^{-4} \;\rm A[/tex]

Thus, we can conclude that the required value of the maximum displacement current of the given space is  [tex]7.08 \times 10^{-4} \;\rm A[/tex].

Learn more about the displacement current here:

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Answer:

If you are talking about the experiment in which mouse and plants are kept in a closed glass jar in sunlight so in that case, they both survive because the CO2 released by the respiration of mouse is being utilized by the plants and fixed ( phosynthesis) and O2 is released as by product, which is taken by the mouse for respiration.

Answer:

16 miles

Explanation:

112 miles/ 7 hours= 16 miles per hour

Answer:

[tex]L=11.3\ kg-m^2/s[/tex]

Explanation:

Given that,

Angular speed of a skater, [tex]\omega=3\ rot/s=18.84\ rad/s[/tex]

The moment of inertia of the skater, I = 0.6 kg-m²

We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :

[tex]L=I\omega[/tex]

Substitute all the values,

[tex]L=0.6\times 18.84\\\\L=11.3\ kg-m^2/s[/tex]

So, its angular momentum is equal to [tex]11.3\ kg-m^2/s[/tex].

Answer:

1/2 m u^2     initial Kinetic Energy of body

m g h        Potential Energy body attains as it rises to height

1/2 m u^2 = m g h      conversion of KE to PE

h = u^2 / ( 2  g)

Answer:20watts

Explanation:

Answer:

The solution is given below

Explanation:

The computation is shown below;

We know that

Work done = Fs cosθ

But before that we need to determine the force i.e.  

We know that

Force (F) = mass (m) × Acceleration (a)

= 100 × 5

= 500 N

Now,  work done by the go-cart is  

Work done (W) = Fs cosθ

= 500 × 25 × cos(0°)

=  500 × 25 × 1

= 12,500 J

Answer:

hippocrates

I guess..........