The reaction K + H2O ⟶ KOH + H2 is an example of?DecompositionSynthesisDouble ReplacementSingle Replacement

Communication with submerged submarines via radio waves is difﬁcult because seawater is conductive and absorbselectromagnetic wa

FrozenT [24]

Answer:

D. 4000 km

Explanation:

f = Frequency of wave that is being transmitted = 76 Hz

$\lambda$ = Wavelength of wave that is being transmitted

v = The velocity of electromagnetic waves through air = $3\times 10^8\ m/s$

Velocity of a wave is given by

$v=f\lambda\\\Rightarrow \lambda=\frac{v}{f}\\\Rightarrow \lambda=\frac{3\times 10^8}{76}\\\Rightarrow \lambda=3947368.42105\ m=3947.36842105 km\approx 4000\ km$

Hence, the approximate wavelength of the waves is 4000 km

8 0

3 years ago

What do stars begin as

Valentin [98]

Cloud of dust and gas!

7 0

3 years ago

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A piano tuner is using a 392 Hz tuning fork to tune the wire for a G-Natural note. She hears 4 beats per second. What are the tw

inysia [295]

A beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies. Frequency beat is equal to,

$f_{beat} =| f_2\pm f_1 |$

The reference frequency in our case would be 392Hz, and since there is the possibility of the upper and lower range for the amount of beats per second that the two possible frequencies are heard would be

$f_{beat} =|392+4|= 396Hz$

$f_{beat} =|392-4|=388Hz$

Therefore the two possible frequencies the piano wire is vibrating at, would be 396Hz and 388Hz

5 0

3 years ago

Explain how a step-down transformer makes electricity safe for use in homes.

Savatey [412]

Answer:

it lowers the voltage in homes

Explanation:

this is due to safety reasons as a human cant survive power line voltages which are between 150k and 760k and if you plugged anything short of a piece of 1 inch thick wire not counting insulation it would immediately start smoking and burn the cable.

3 0

3 years ago

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Jake is helping Fin push a box at a constant velocity up an incline that makes an angle of 30.0° above the horizontal by applyin

andre [41]

Given data

The angle of inclination of the plane is theta = 30 degree

The applied force in the inclined plane is F = 94 N

The distance moved in the inclined plane is d = 2.30 m

The coefficient of kinetic friction is u_k = 0.280

The free-body diagram of the above configuration is shown below:

Here, the normal reaction force on the box is N, the acceleration due to gravity is denoted as g, the friction force on the box is F_f, and the mass of the box is denoted as m.

(a)

The expression for the work done by the pushing force is given as:

$W=Fd$

Substitute the value in the above equation.

$\begin{gathered} W=94\text{ N}\times2.30\text{ m} \\ W=216.2\text{ J} \end{gathered}$

Thus, the work done by the pushing force is 216.2 J.

(b)

The box is moving at the constant velocity, therefore, the pushing force will be equal to the frictional force and the component of the gravitational force in the inclined plane.