Helpppp guys plsss help !

When an underwater sound source emits waves of frequency 30 kHz in all directions, the intensity of the waves (in Watts/m2) vary with distance r from the source by the relation 1/r²

As the intensity mechanical sound wave is inversely proportional to the square of the distance from the source, therefore the correct option is B.

Wavelength can be understood in terms of the distance between any two similar successive points across any wave for example wavelength can be calculated by measuring the distance between any two successive crests.

It is the total length of the wave for which it completes one cycle.

The intensity of a mechanical wave is inversely proportional to the square of the distance from the source.

An underwater sound source emits waves of frequency of 30 kHz in all directions, the intensity of the waves (in Watts/m2) varies with distance r from the source by the relation 1/r², therefore the correct option is B.

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Answer:

The size of the magnetic force on the wire due to the Earth's magnetic field is 4.62 × 10⁻⁶ N.

Explanation:

To determine the size of the magnetic force on the wire due to the Earth's magnetic field,

The magnetic force is given by the formula

F = ILB sinθ

Where F is the magnetic force on the wire

I is the electric current in Amperes (A)

L is is the length of wire in meters (m)

B is the magnetic field in Tesla (T)

and θ is the angle between current and magnetic field

From the question,

L = 0.30 m

I = 0.50 A

B = 0.50 gauss = 0.5 × 10⁻⁴ T (NOTE: 1 Gauss = 10⁻⁴ Tesla)

θ = 38°

Now, putting the values into the equation

F = ILB sinθ

F = 0.50 × 0.30 × 0.5 × 10⁻⁴ sin38°

F = 7.5 × 10⁻⁶ (0.61566)

F = 4.62 × 10⁻⁶ N

Hence, the size of the magnetic force on the wire due to the Earth's magnetic field is 4.62 × 10⁻⁶ N.

Answer:

19.3 m/s

Explanation:

Take down to be positive.  Given:

Δy = 19 m

v₀ = 0 m/s

a = 9.8 m/s²

Find: v

v² = v₀² + 2aΔy

v² = (0 m/s)² + 2 (9.8 m/s²) (19 m)

v = 19.3 m/s

Answer:

a. the amount of work done on a system is dependent of pathway

Explanation:

The first law of thermodynamics states that the change in internal energy of a system equals the net heat transfer into the system minus the net work done by the system.

ΔU = Q - W

Where;

Q, the net heat transfer into the system depends on the pathway

W, the net work done by the system also depends on the pathway

But, ΔU, the change in internal energy is independent of pathway

Therefore, the correct option is "A"

a. the amount of work done on a system is dependent of pathway

Answer:

Induced emf = 0

Explanation:

An emf can be induced due to the change in magnetic field. It can be given by :

[tex]\epsilon=\dfrac{d\phi}{dt}\\\\\because \phi=BA\cos\theta\\\\\epsilon=\dfrac{d(BA\cos\theta)}{dt}\\\\\epsilon=A\cos\theta\dfrac{dB}{dt}[/tex]

As the loop is placed perpendicular to a uniform magnetic field of 1 Tesla. It means that [tex]\theta=90^{\circ}[/tex] and cos(90) = 0. Hence, the induced emf is equal to 0.

Answer:

Approximately 17.21 seconds

Explanation:

With subtraction, we have the gazelle 18.3 km/h slower than the cheetah, which is about 5.08333 m/s. As the gazelle is 87.5 meters ahead of the cheetah, 87.5 divided by 5.083333333 is about 17.21 seconds.

Answer:

-) It is less than 8 [N]

See the explanation below.

Explanation:

To solve this problem we must analyze each of the answers, and in this way, we will come to the right solution. The most important thing is to keep in mind that the body is moving to the left.

-) It is equal to 8 [N]

This answer is not possible, since if the Force F was equal to 8 [N] the body would be in equilibrium and the body would not move.

-)  It is equal to 10 [N]

This answer is not possible, since if Force F is greater than 8 [N] the body would move to the right.

-)  It is greater than 10 [N]

This answer is not possible, since if Force F is greater than 8 [N] the body would move to the right.

-) It is less than 8 [N]

This is the correct option, as the force of 8 [N] will move the body to the left.

Answer:

Sound travels slower than light

Explanation:

Sound travels at around 1/3 km per second, while light travels around 300,000 km per second.

Also, this is the reason you see the lightning before you hear the thunder.

I hope this helped.

Answer:

Sound travels slower than light

Explanation:

Bc light is faster than sound

Answer:

the set of all real numbers

Explanation:

Given the cost of the magazine expressed as:

c=45+3.75m where:

c describes the cost of the yearly subscription.

m is the amount of order.

You must understand that domain are the values of the input variable m that will make the function exist.

The value of m that will produce a positive output since we can only have a positive value of the cost. According to the option, we can say that the domain is on the set of all real numbers (some are negative but all positive real numbers)

Answer:

a) 1.4 m/s2

b) 63N

c) 6.66kg

Answer:

The maximum energy that can be transferred to an electron in a single collision of alpha particle is 1.63 keV

Explanation:

let mass of electron, Me = 1

let mass of proton, Mp = 1836Me = 1836

let mass of alpha particle, Ma = 4Mp = 7344

The maximum energy that can be transferred to an electron in a single collision is given by;

[tex]Q_{max} = \frac{4mME}{(M+m)^2}\\\\Q_\alpha_{max} = \frac{4(1)(7344)(3\ MeV)}{(1+7344)^2} = 0.00163 \ MeV = 1.63 \ KeV[/tex]

Therefore, the maximum energy that can be transferred to an electron in a single collision of alpha particle is 1.63 keV

Answer:

give us some further context to answer your question as well

Explanation:

Answer:

Mass was added to the water particles, resulting in deposition.

Explanation:

Answer:  The energy was removed from the water particles resulting in condensation

Explanation Think about when you leave a cup of ice of and after a while you see water droplets thats what happened to the grass in the morning and thats called condensation.

Which object? More information is needed to answer this question

Answer:

answer: 105 sin 30 = 52.5

Answer: The motion of a ball falling down through the atmosphere, or a model rocket being launched up into the atmosphere are both examples of Newton's first law. The motion of a kite when the wind changes can also be described by the first law.

Explanation:

Answer:

We are given:

m = 1500 kg

initial velocity (u) = 35 m/s

final velocity (v) = 0 m/s

time (t) = 5 seconds

acceleration = a m/s/s

Force (f) = F  newtons

Solving for acceleration:

Using the first equation of motion:

v = u + at

replacing the variables

0 = 35 + a(5)

a = -35/5

a = -7 m/s/s

Force applied by the brakes:

From newton's second law of motion:

F = ma

replacing the variables

F = (1500)(-7)

F = -10500 N

Therefore, the force applied by the brakes is -10500 N, we have a negative sign since the force is being applied opposite to the direction of motion

Answer:

Yes, the number of electrons determines the chemical properties of the atom.

Explanation:

Answer:

Vy = 24.01 [m/s]

Explanation:

To solve this problem we must understand that velocity is a vector and therefore has magnitude and direction, in this way we can decompose the velocity in the components x & y, by means of the trigonometric functions of the sine and cosine of the angle.

For the vertical component, the sine of the angle is used.

Vy = 25.79*sin(68.64)

Vy = 24.01 [m/s]

Complete Question

A 940-g rock is whirled in a horizontal circle at the end of a 1.30-m-long string,  If the breaking strength of the string is 120 N, what's the minimum angle the string can make with the horizontal?

Answer:

The value is [tex]\theta = 4.41^o[/tex]      

Explanation:

From the question we are told that

  The mass of the rock is  [tex]m_r = 940 \ g = 0.94 \ kg[/tex]

   The length of the string is [tex]l = 1.30 \ m[/tex]

    The breaking strength(i.e the maximum tension) on the string is [tex]T = 120 \ N[/tex]

Gnerally the vertical component of the tension experienced by the string is mathematically represented as

     [tex]T_v = T sin(\theta)[/tex]

Generally this vertical component  of tension is equivalent to the weight of the rock

So

     [tex]Tsin (\theta) = mg[/tex]

=>  [tex]\theta = sin^{-1} [\frac{mg}{ T} ][/tex]

=>    [tex]\theta = sin^{-1} [\frac{0.940 *9.8 }{ 120} ][/tex]

=>    [tex]\theta = 4.41^o[/tex]      

If we assume the collision to be elastic the final velocity of the ball will be  -8.65 m/s, therefore the correct option is D.

It is a type of Collison for which the momentum, as well as the kinetic energy after and before the collision, is constant. there is no loss of energy in a perfectly elastic collision.

By using the law of conservation of momentum

momentum before collision = momentum after the collision

the initial momentum of rocket +initial momentum, of ball = final momentum of rocket + final momentum of the ball

By substituting the respective values

-1.75 + 0.00684 = -1.25 + m*v

-1.75 + 0.00684 = -1.25 + 0.057*v

v = -8.65 m/s

Thus, the final velocity of the ball is -8.65 m/s

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Answer:

The second choice

Explanation:

I think the answer is the second choice because if the surface is smooth, there is less friction. With a boat, it is easier to pull it on water than on the sand, because water has less friction, and thus, the answer is the second choice because rough surfaces have more friction.

Hopefully the explanation and answer helps!

Answer:

[tex]h_p = 30.46\ m[/tex]

Explanation:

Free Fall Motion

A free-falling object refers to an object that is falling under the sole influence of gravity. If the object is dropped from a certain height h, it moves downwards until it reaches ground level.

The speed vf of the object when a time t has passed is given by:

[tex]v_f=g\cdot t[/tex]

Where [tex]g = 9.8 m/s^2[/tex]

Similarly, the distance y the object has traveled is calculated as follows:

[tex]\displaystyle y=\frac{g\cdot t^2}{2}[/tex]

If we know the height h from which the object was dropped, we can solve the above equation for t:

[tex]\displaystyle t=\sqrt{\frac{2\cdot y}{g}}[/tex]

The stadium is h=32 m high. A pair of glasses is dropped from the top and reaches the ground at a time:

[tex]\displaystyle t_1=\sqrt{\frac{2\cdot 32}{9.8}}=2.56\ sec[/tex]

The pen is dropped 2 seconds after the glasses. When the glasses hit the ground, the pen has been falling for:

[tex]t_2=2.56 - 2 = 0.56\ sec[/tex]

Therefore, it has traveled down a distance:

[tex]\displaystyle y=\frac{9.8\cdot 0.56^2}{2} = 1.54\ m[/tex]

Thus, the height of the pen is:

[tex]h_p = 32 - 1.54\Rightarrow h_p=30.46\ m[/tex]

The pen is 30.52 m above the ground.

Given that the height of the stadium is h = 32m

The initial velocity of the glasses will be 0.

[tex]h=\frac{1}{2}gt^{2} \\t=\sqrt{\frac{2h}{g} } \\t=\sqrt{\frac{2*32}{9.8} }\\t=2.55s[/tex]is the time taken for the glasses to hit the ground.

Now the pen is released 2 seconds later. So by the time the glasses hit the ground the pen has spent:

[tex]t^{'}=2.55-2\\t^{'}=0.55s[/tex]in the air

distance traveled by the pen:

[tex]d=\frac{1}{2}gt^{2}\\\\d=\frac{1}{2}*9.8*0.55*0.55\\\\d=1.48m[/tex]

So the pen is  [tex]h-d=32-1.48=30.52m[/tex]  above the ground.

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Answer:

Can become non-renewable but it depends on the object

Explanation:

Answer:

Renewable resources are so abundant or are replaced so rapidly that, for all practical purposes, they can't run out. Fossil fuels are the most commonly used non-renewable resources

Explanation:

Hope this helps (:

Answer:

when your heart rate is not high than normal or lower than normally

Explanation:

Recovery heart rate is when your heart recovers from a certain heart rate eg high heart rate or even low heart rate this means you heart is now functioning normally .

Answer:

Number of beats per minute the heart drops after exercise.

Complete Question

The complete question is shown on the first uploaded image

Answer:

The value is  [tex]v = 9.18 *10^{6} \ m/s[/tex]

Explanation:

From question we are told that

  The potential  difference is  [tex]\Delta V = 0.24 kV = 0.24 *10^{3} \ V[/tex]

Generally the the non-relativistic speed of these electrons  is mathematically represented as

       [tex]v = \sqrt{\frac{2 * e * \Delta V}{m} }[/tex]

Here  m is the mass of an electron with value [tex]m = 9.11 *10^{-31 } \ kg[/tex]

           e  is the charge on an electron with value  [tex]e = 1.60 *10^{-19} \ C[/tex]

So

        [tex]v = \sqrt{\frac{2 * 1.60 *10^{-19} * 0.24 *10^{3} }{9.11*10^{-31}} }[/tex]

=>   [tex]v = 9.18 *10^{6} \ m/s[/tex]

Answer:

22.3 kg•m/s

Explanation:

Apex;)