What is polarization. How can we remove it?

Answer:

B. its speed increases

Explanation:

A brass rod is encased in aluminium. The speed of a sound wave in this decreases when it moves from the aluminium into the brass medium. Thus, the correct option is A.

Sound travels in different mediums in the form of waves. The speed of sound is the speed with which the sound wave travels in a medium. The speed of the wave depends on the density and the elasticity of the medium through which the sound waves travel. In general, the sound wave travels faster in the liquid mediums in comparison to the gas medium and these are quicker in solid mediums than in liquid mediums. Thus, the greater the elasticity and the lower the density of the waves, the faster the sound waves travel in that medium.

The speed of sound in aluminium is 5100m/s and in the brass medium, it is 6,923. So, if the sound wave is moving from aluminum metal to the brass medium, we can clearly observe that there is decrease in the speed of sound. So, we can say here that is the speed is decreases.

Therefore, the correct option is A.

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Complete question :

Tony drives his car . He drives the first 13 miles in 13 minutes. He then drives at an average speed of 68mph for 1 hour 24 minutes . Find how much petrol he uses using the information in the table.

Requires table to answer question is attached below

Answer:

2.64 gallons

Explanation:

Given that:

First 13 miles takes 13 minutes

Average rate = 13 miles / 13 minutes = 1mile/minute ; Average rate per hour = (1 mile /minute * 60) = 60 miles /hour

If average speed = 65mph or less ; 50 miles per gallon (it uses 1 gallon for 50 miles)

Hence, since first phase rate is 60 mph,; then miles per gallon is 50 miles

Therefore,gallon of petrol used for 13 miles will be :

13 miles / 50 mpg = 0.26 gallons

2nd phase:

Average rate of 68 mph for 1 hour 24 minutes (1.4 hours)

Here, miles per gallon = 40 (that is; 40 miles for 1 gallon).

Total distance covered = 68 * 1.4 = 95.2 miles

Petrol used = 95.2 miles / 40 mpg = 2.38 gallons

Hence,

Total petrol used : (0.26 + 2.38) = 2.64 gallons

Answer:

The actual angle is 30°

Explanation:

[tex]v_y(t)=vo*sin(A)-g*t[/tex]

the velocity is Zero when the projectile reach in the maximum altitude:

[tex]0=vo-gt\\t=\frac{vo}{g}[/tex]

When the time is vo/g the projectile are in the middle of the range.

[tex]d_x(t)=vo*cos(A)*t\\[/tex]

R=Range

[tex]R=d_x(t=2*\frac{vo}{g})[/tex]

[tex]R=vo*cos(A)*2\frac{vo}{g} \\\\R=\frac{(vo)^{2}*2* sin(A)cos(A)}{g} \\\\R=\frac{(vo)^{2} sin(2A)}{g}[/tex]

**sin(2A)=2sin(A)cos(A)

Let B the actual angle of projectile

[tex]\frac{vo^{2} }{g} =(\frac{2}{\sqrt{3} }) \frac{vo^{2} *sin(2B)}{g}\\\\1= \frac{2 }{\sqrt{3}} *sin(2B)\\\\sin(2B)=\frac{\sqrt{3}}{2}\\\\[/tex]

2B=60°

B=30°

Answer:

5.00 x 10^9 j

Explanation:

mass = 100 kg

speed / velocity = 10 km/s x 1000 = 10,000m

K.E =

[tex] \frac{m{v}^{2} }{2} [/tex]

10,000x 100/ 2

= 5000000000

= 5.0 x 10^9j

Answer:

salt dissolving

Explanation:

hope it helps

Answer:

[tex]g=G\frac{m_E}{r^2}[/tex]

Explanation:

Using Newton's Law of Universal Gravitation, we can write:

[tex]F=G\frac{m_E}{r^2}[/tex], where [tex]G[/tex] is gravitational constant [tex]6.67\cdot 10^{-11}[/tex], [tex]m_E[/tex] is Earth's mass, and [tex]r[/tex] is Earth's radius.

Using these measured values, we have:

[tex]F=6.67\cdot 10^{-11}\frac{5.97\cdot 10^{24}}{(6.38\cdot10^6)^2},\\g\approx \fbox{$9.8\:\mathrm{m/s^2}$}[/tex].

Answer:

3.06m/s² to the east

Explanation:

Given parameters:

Mass of car = 2.5 x 10³kg

Force acting on the car  = 7.65 x 10³N

Unknown:

Acceleration of the car  = ?

Solution:

From Newton's second law of motion:

      Force  = mass x acceleration

   Acceleration  = [tex]\frac{Force }{mass}[/tex]   = [tex]\frac{7.65 x 10^{3} }{2.5 x 10^{3} }[/tex]    = 3.06m/s² to the east

Answer:50mph

Explanation:

Answer:

a) 24.33 m of distance.

b) 34.55° east of the south.

Explanation:

The question is incomplete. The whole exercise is the following:

"Ricardo and Jane are standing under a tree in the middle of a pasture. An argument ensues, and they walk away in different directions. Ricardo walks 28.0 m in a direction 60.0° west of north. Jane walks 12.0 m in a direction 30.0° south of west. They then stop and turn to face each other.

(a) What is the distance between them?

(b) In what direction should Ricardo walk to go directly toward Jane?"

Now that we know what we need to do in this question, let's head for every part of the problem.

a) Distance between Ricardo and Jane

In this case, we need to analyze the given data:

Ricardo (which we will call R) is 28 m from the starting point at 60° west of north, and Jane (J) is 12 m at 30° south of west. So the distance between them, will be the point where they both stop and face each other. This point can be seen in the image attached (See picture).

Let's call the distance between them as "D", to get the distance of D, according to the picture will be:

D = J - R   (1)

However, as they are facing in different angles and directions, we cannot do the difference of their values distance just like that. In order to do that, we need to calculate the components in the "x" and "y" axis of each vector. In that way, we can get the components of x and y of the Distance D, and then, the whole distance between them will be:

D = √Dx² + Dy²     (2)

So, let's get the components of x and y of R and J.

For Ricardo (R):

Rx = R sin60° = 28 sin60° = -24.25 m

Ry = R cos60° = 28 cos60° = 14 m

The sign "-" it's because R it's on the second quadrant, therefore in x, we'll have to add the negative.

For Jane (J):

Jx = J cos30° = 12 cos30° = -10.39 m

Jy = J sin30° = 12 sin30° = -6 m

Again, the negative is added because J is on the third quadrant.

Now that we have the components, let's calculate vector D using expression (1):

Dx = -10.39 - (-24.25) = 13.86 m

Dy = -6 - 14 = -20 m

Now, using expression (2) we can finally know the distance between Jane And Ricardo:

D = √(-20)² + (13.86)²

This is the distance between Jane and Ricardo.

b) Direction of Ricardo walking to Jane

In this case, we already have the components of x and y of the distance between them, so, to know the direction:

Tanα = Dy/Dx

α = tan⁻¹ (Dy/Dx)

Replacing the values we have:

α = tan⁻¹ (-20/13.86)

α = 55.45°

Which should south of east or:

β = 90 - 55.45

Ricardo should walk 34.55° east of south

Hope this helps

Answer:

gravity is the force by which a planet or another body draws objects towards its Centre. the force of gravity keeps all of the planets in an orbit around the sun.

Explanation:

what is gravity made of?

gravity are made of proposed gravity parts that are made quantum particles which called gravitational anywhere there is gravitation there is gravity like on Earth in the Solar System most importantly in the minisclue infant and intervention universe .

Answer:

the last one

Explanation:

its the sun when the earth turns towards the sun it gives us heat not solar radiation.

Answer:

Average speed = 60km/hr

Explanation:

Given the following data;

Time = 2.5 hrs

Distance = 150km

To find the average speed;

Average speed = distance/time

Substituting into the equation, we have

Average speed = 150/2.5

Average speed = 60km/hr

Answer:

Below are some of the important dates that led to the creation of the Constitution: 1775 — The Revolutionary War between the Colonies and Britain begins. ... 1781 — The last battle of the Revolutionary War takes place; the 13 states set up a federal government under laws called the Articles of Confederation.

Explanation:

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Answer:   b or c

Explanation:  on khan academy

Answer:

Venus is only 95% the size of Earth, and 81% of its mass. With the smaller size and mass, the force of gravity pulling you on the surface is lower. To get your weight on Venus, just multiply your current weight by 0.9. That's why 100 pounds becomes 90 pounds

If the mass of an object is 35kg on Venus Its mass on the Sun remains the same hence the object's mass om sun in 35 kg. The mass of an object is an intrinsic property and remains the same regardless of the gravitational field.

The mass of an object does not change depending on its location. The mass of an object is an intrinsic property and remains the same regardless of the gravitational field it is in or its location within the universe.

However, it is important to note that an object's weight, which is the force of gravity acting on it, would be different on Venus and the Sun due to the variations in gravitational pull.

Therefore, if the mass of an object is 35 kg on Venus, its mass would still be 35 kg on the Sun.

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Answer:

V₁ = 200 mi/h

Explanation:

To do this, we need to analyze the given data.

We have a total distance and time of 1500 mi and 6.5 h. We also know that the second plane goes 50 mi/h faster than the first plane, (V₂ = V₁ + 50). The firsts 500 miles were on the first plane and the remaining 1000 mi with the second plane.

Using the expression of distance, and assuming a constant speed in both planes we have:

d = V * t   (1)

Replacing this expression for both planes we have:

d₁ = V₁ * t₁

d₂ = (V₁+50) * t₂

WE are missing several data, because we do not know the times for each plane, but we can have a clue.

The total time of flight was 6.5 h, this is equivalent to just sum both times of both planes, so:

t = t₁ + t₂   (3)

From the expressions of distance for both planes, we can solve for time, and then replace in the above expression of the total time. In that way we can solve for the speed of the plane. Let's solve for both times in the planes:

t₁ = d₁ / V₁ = 500/V₁    (4)

t₂ = d₂ / V₁+50 = 1000/ V₁ + 50   (5)

Now, all we have to do is replace (4) and (5) into (3) and solve for V₁:

6.5 = [(500/V₁) + (1000/V₁ + 50)

6.5 = [500*(V₁+50) + 1000V₁ / V₁(V₁+50)]

6.5 = [500V₁ + 25000 + 1000V₁ / V₁² + 50V₁

6.5(V₁² + 50V₁) = 1500V₁ + 25000

6.5V₁² + 325V₁ - 1500V₁ - 25000 = 0

6.5V₁² - 1175V₁ - 25000 = 0

From here, we use the quadratic equation to solve for V₁:

X = 1175 ± √(1175)² + 4 * 6.5 * 25000 / 2 * 6.5

X = 1175 ± √1380625 + 650000 / 13

X = 1175 ± 1425 / 13

X₁ = 1175 + 1425 / 13 = 200

X₂ = 1175 - 1425 / 13 = -19.23

So, it's very clear that the speed cannot be negative, so we stick with the first value. Therefore the speed pf the first plane is:

Hope this helps

The speed of the first plane is 77.02 mph.

The given parameters:

Let the average speed of the first plane = v

Then, average speed of the second plane = 50 + v

The speed of the first plane is calculated as follows;

[tex]\frac{500}{v} + \frac{100}{50 + v} = 6.5\\\\\frac{500(50 + v) + v}{v(50 + v)} = 6.5\\\\500(50 + v) + v = 6.5(50v + v^2)\\\\25000+ 500v + v = 325 v + 6.5v^2\\\\6.5v^2 -176 v - 25000 = 0\\\\a = 6.5, \ b = -176, \ c = -25000\\\\v = \frac{-b \ +/- \ \ \sqrt{b^2 - 4ac} }{2a} \\\\v = 77.02 \ mph[/tex]

Thus, the speed of the first plane is 77.02 mph.

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Answer:

The particles gain more kinetic energy and begin to move faster

Explanation:

Based on the kinetic theory of matter, matter is made up of particles, which are in a constant state of random motion.

This means that the tiny particles of the metal tray are continuously moving about. Furthermore, for the particles to move about, they need energy. This can come in various forms. It can be chemical, kinetic, or light, etc.

Once the metal tray is placed in the oven the particles get some kinetic energy from the heat of the hot oven. The metal particles begin to vibrate about their mean position a lot quicker than ever before. This leads to an increase in the temperature of the metal tray.

If this continues, they will be able to break the metallic bonds holding them together, causing a change of state from solid to liquid, which we will be able to perceive as the melting of the tray.

Answer:

100

Explanation:

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Velocity includes both speed and direction.

Velocity of a particle is its speed and the direction in which it is moving.

It can also be described as the instantaneous rate of change of the particle's distance traveled, and the direction in which the distance is changing, velocity is basically speeding in a specific direction. It is a vector quantity, which means we need both magnitude (speed) and direction to define velocity. The SI unit of it is metre per second (ms-1). If there is a change in magnitude or the direction of the velocity of a body, then it is said to be accelerating.

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Answer:

A

Explanation:

No change in direction, and travel was in a straight line, and total distance travelled is 9+5=14

Answer:Stronger they are

(I think...)

Answer:

Starting from the beginning.

There is a radio signal that is received by the radio.

The radio interprets the signal and produces a current in response to it.

That current goes to a membrane that oscillates producing sound, the oscillation of the membrane is the first mechanical energy event here.

These oscillations can travel in material mediums, for example, the air. Then there is a production of waves (soundwaves) that travel in the air (second event).

Those waves now hit the wall that separates you and your neighbor, as the wall is made of a material, the soundwaves can travel through it, but they will be dispersed (a part of the waves rebounds on the wall, and another part is dissipated as the wave travels through the wall), there is also a transmitted part of the wave, that is now in your house. (this change of medium will be the third event). Now only the lower frequencies survive, this is why the sound is "muffled".

Those remaining frequencies now travel in your house, and when they reach your ear, your ear sends a signal to your brain and your brain interprets them as sound. The wave interacting with your ear will be the fourth and last mechanical energy event.