Alkaline earth metals have a low density


true
false

Answer:

West coast

Explanation:

i think this is the ans

Answer:

huh? I think it's Power.....

Answer:

3

ExplSpanisshh

Answer: A. silicon and oxygen

Explanation:

The two most abundance elements in earth's crust are silicon and oxygen.

The most abundant element in earth's crust is Oxygen (O) which has a percentage composition of 46.6%.  Oxygen is mainly present as silicates, carbonates, sulphates etc.

The second most abundant element in earth's crust is Silicon (Si) which has a percentage composition of 27.7% . Silicon is present in the form of silicates.

The third most abundant element in earth's crust is aluminium (Al) which has a percentage composition of 8.1 %.

The fourth most abundant element in earth's crust is Iron (Fe) which has a percentage composition of 5.0 %.

Answer:

A

Explanation:

Answer:

I don't know if these are all right but these are my best answers. good luck and I hope you do well.

1. true

2. true

3. false

4. true

5. true

6. true

7. true

8. true

9. false

10. false

13. it stimulates the heart through chest compressions

14. on bare skin upper right shoulder and lower left ribs

15. no CPR

Explanation:

The period of the sound wave having frequency of 457Hz is 0.0022 s.

The frequency refers to the number of waves that pass a fixed point in unit time.

Time period is equal to the reciprocal of frequency.

                           i.e. T = 1 / f

So, The period of the sound wave having frequency of 457Hz will be

                                T = 1/457

                            ∴ T = 0.002188 s

Now , rounding to the nearest value we get , 0.0022 s

Thus , The period of the sound wave having frequency of 457Hz is 0.0022 s.

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Answer:

Explanation:

Total Mass: 48+25=73 kg

Height: 15m

So work = mgh= 73×9.8× 15=10731 j

And this is positive work.

Answer:

Since heat is carried by electromagnetic waves, it does not need a physical medium to transfer it. Instead it radiates through space - this is how the Earth is heated by the Sun despite space being a vacuum.

Explanation:

Answer:

a) time taken = 1.427 s

b) final speed before hitting the ground = 14 m/s

Explanation:

height of cliff = 10 m

acceleration due to gravity = 9.81 [tex]m/s^{2}[/tex]

time taken for stone to reach bottom of cliff = ?

velocity of stone just before hitting the ground = ?

To find the time taken, we will use Newton's equation of motion

using

[tex]v^{2} = u^{2} + 2as[/tex]

where

v = final speed of stone before hitting the ground

u = initial speed of the stone (u = 0 since the stone started falling from rest)

a = acceleration due to gravity = 9.81 [tex]m/s^{2}[/tex]

s = height of the cliff = 10 m

Solving, we have

[tex]v^{2} = 0^{2} + 2(9.81 * 10)[/tex]

[tex]v^{2} = 2*98.1[/tex]

[tex]v^{2} = 196.2[/tex]

[tex]v=\sqrt{196.2} = 14 m/s[/tex]

From the first equation of motion,

[tex]v = u + at[/tex]

where t = time taken for stone to reach bottom of cliff

imputing values, we have

[tex]14 = 0 + (9.81 * t)[/tex]

[tex]t = \frac{14}{9.81} = 1.427 s[/tex]

Answer:

ΔK = -6 10⁴ J

Explanation:

This is a crash problem, let's start by defining a system formed by the two trucks, so that the forces during the crash have been internal and the moment is preserved

initial instant. Before the crash

        p₀ = m v₁ + M 0

final instant. Right after the crash

        p_f = (m + M) v

        p₀ = p_f

        mv₁ = (m + M) v

        v = [tex]\frac{m}{m+M} \ v_1[/tex]

we substitute

        v = [tex]\frac{20}{20+40}[/tex]   3

        v = 1.0 m / s

having the initial and final velocities, let's find the kinetic energy

        K₀ = ½ m v₁² + 0

        K₀ = ½ 20 10³ 3²

        K₀ = 9 10⁴ J

        K_f = ½ (m + M) v²

        K_f = ½ (20 +40) 10³  1²

        K_f = 3 10⁴ J

the change in energy is

       ΔK = K_f - K₀

       ΔK = (3 - 9) 10⁴

       ΔK = -6 10⁴ J

The negative sign indicates that the energy is ranked in another type of energy

Answer:

Air resistance/Drag (this is the proper term for air resistance) or gravity or friction

It depends on the direction and if you throw it across a surface or if you throw it straight upwards.

I hope this helps!!

Answer:

Newton's first law: An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.

Explanation:

Answer:

[tex]f=5.76\times 10^{14}\ Hz[/tex]

Explanation:

We need to find the frequency of green light having wavelength o[tex]5.2\times 10^{-7}\ m[/tex]. It can be calculated as follows :

[tex]c=f\lambda\\\\f=\dfrac{c}{\lambda}\\\\f=\dfrac{3\times 10^8}{5.2\times 10^{-7}}\\\\f=5.76\times 10^{14}\ Hz[/tex]

So, the required frequency of green light is equal to [tex]5.76\times 10^{14}\ Hz[/tex].

Answer:

It is hard to push the empty upside down mug inside the water as it has air present inside its cavity which prevents the water from entering inside the mug.

I hope this helps a little bit.

Answer:

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field.

Explanation:

Answer:

Explanation:

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. ... Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time.

Answer:

d

Explanation:

Answer:

1788.402 MJ

Explanation:

Work done = Force (N) x distance (m)

First we have to convert distance into metres:

173.8 x 1000 = 173,800 m

Then plug these values into the equation above:

173,800 x 10290 = 1788402000 J

The reason it's Joules (the unit for energy) is because work done = energy transferred

Now we have to convert Joules into Mega Joules:

1 J = 1/1000000 MJ

1788402000 J = 1788402000/ 1000000 = 1788.402 MJ

Answer:

dttydghcghcghdytdftygfvghxk,ghc

Explanation:

Answer:

wave

Explanation:

A wave is defined as the disturbance that causes the movement of energy. The energy is transferred as the waves move from one place to another. A medium is required for the transfer of energy. Usually a wave travels through air or water. The process is carried on at a specific speed that is termed as the speed of propagation.

Answer:

A

Explanation:

The image that shows an alignment of earth, moon and sun during spring tide is option A. All of them will be in a straight line.

A spring tide is a type of tide that occurs when the Earth, sun, and moon are aligned in a straight line. During a spring tide, the gravitational pull of the sun and the moon combine, resulting in higher-than-normal high tides and lower-than-normal low tides.

During a spring tide, the position of the sun, moon, and earth is aligned in a straight line. The gravitational force of the moon and sun both act upon the oceans of the Earth, creating a combined effect that results in unusually high tides.

During a spring tide, the moon is either new or full, which means it is in a position that aligns with the sun and Earth. The gravitational pull of the moon and sun reinforce each other, creating a stronger gravitational force on the Earth's oceans.

This causes the water level to rise higher than normal during high tide and lower than normal during low tide. Here, image A shows the correct alignment.

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Answer:

E = 24000 N/C = 24 KN/C

Explanation:

The electric field experienced by a test charge is given by the following formula:

[tex]E = \frac{F}{q}\\\\[/tex]

where,

E = Electric Field = ?

F = Force of attraction = 3 x 10⁻⁶ N

q = Charge on piece of lint = 1.25 x 10⁻¹⁰ C

Therefore, using these values in the equation, we get:

[tex]E = \frac{3\ x\ 10^{-6}\ N}{1.25\ x\ ^{-10}\ C}\\\\[/tex]

E = 24000 N/C = 24 KN/C

Answer:

 t = 6.6 10⁻⁸ m

Explanation:

In this case we have that the reflection in the film is constructive, we take into account that

* When the light is reflected from the air (n = 1) to the film (n=2) it has a phase change of 180º

* within the film the wavelength is modulated by the index of refact

          λₙ = λ₀ / n

taking into account these two aspects the expression for constructive interference is

         2n t = (m + ½)  λ₀

let's find the minimum thickness (t) of the film

         t = (m + ½)  λ₀ / 2n

for m = 0

        t = ½   527 10⁻⁹ /(2 2.00)

        t = 6.6 10⁻⁸ m

Answer:

25% :)

Explanation:

Answer:

A. 13.3

Explanation:

First, we find the velocity of the electron in meters/sec, as follows:

[tex]v = \frac{d}{t}\\[/tex]

v = velocity of electron = ?

d = distance between plates = 2 cm = 0.02 m

t = time elapsed = 1.5 x 10⁻⁸ s

Therefore, using these values in the equation, we get:

[tex]v = \frac{0.02\ m}{1.5\ x\ 10^{-8}\ s}\\\\v = 1333333.33\ m/s[/tex]

Now, we convert this to million m/s:

[tex]v = (1333333.33\ m/s)\frac{1\ million\ m}{100000\ m}\\\\v =13.3\ million\ m/s[/tex]

Therefore, the correct answer is:

A. 13.3

Answer:

Hope this helps you out if you could please leave 5 stars or brainiest thank you

Answer:

we can't cry in space like we do earth.... because there is no gravity... due to which the tears not fall down..instead they make a liquid clump...near eyes

Answer:

b

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Answer:

Frequency

Explanation:

I just took that test