In a whispering gallery, a person standing at one focus of the ellipse can whisper and be heard by another person standing at the other focus, because all sound waves that reach the ceiling from one focus are reflected to the other focus. A hall 120 feet in length is to be designed as a whispering gallery. Of foci are located 40 feet from the center, how high will the ceiling be at the center

Answer:

because potentil energy is redy to go but its bound up

And kinetic energy is in motion

Explanation:

Answer:

Explanation:

Definitely NOT! Mass is unchanging, wherever you go. On the moon you will have the same mass as you will on the earth. Mass is just a measure of the matter that makes up a body. Weight, however, is dependent upon the pull of gravity which is different on earth than it is on the the moon, for example.

Mass doesn't change with proximity whereas weight can.

Answer: No

Explanation: The terms'mass' and 'weight' are frequently used interchangeably, yet they have distinct meanings. Your mass remains constant regardless of where you are in the universe; nevertheless, your weight varies. The mass of anything is a measure of how much power is required to change its course.

Answer:

Both have equal impulse.

Explanation:

Let the mass of cars be m.

Then the Force acting on each of them for taking them to state of rest:

(Using Newton's second law of motion)

[tex]F_A=\frac{m\times (0-30)}{\Delta t_A}[/tex]

[tex]F_A=-30\frac{m}{\Delta t_A}[/tex] ...................................(1) (negative sign is associated with direction, here we are concerned about the magnitude only)

[tex]F_B=\frac{m\times (0-30)}{\Delta t_B}[/tex]

[tex]F_B=-30\frac{m}{\Delta t_B}[/tex] ...................................(2)

[tex]\because \Delta t_A<\Delta t_B[/tex]

[tex]\therefore F_A>F_B[/tex]

We know that impulse is given as:

[tex]J=F\times \Delta t[/tex] ........................................(3)

So, from eq. (1), (2) & (3)

[tex]J_A=F_A\times \Delta t_A[/tex]

[tex]J_A=-30m[/tex]

&

[tex]J_B=F_B\times\Delta t_A[/tex]

[tex]J_B=-30m[/tex]

Hence both have equal impulse.

Answer:

What languages do i sqeak?

English, Korean and Filipino

Uhh why are you asking it?

Answer:

The pressure of the gas=4.002 atm

Explanation:

We are given that

R=0.0821

Number of moles, n=15

Temperature, T=299 K

Volume of gas, V=92 L

We have to find the pressure of the gas.

[tex]PV=nRT[/tex]

Substitute the values

[tex]P\times 92=15\times 0.0821\times 299[/tex]

[tex]P=\frac{15\times 0.0821\times 299}{92}[/tex]

[tex]P=4.002 atm[/tex]

Hence, the pressure of the gas=4.002 atm

Answer:

According to the ideal gas law equation,

PV = nRT               (here, P = 5.5 atm, V = 10L, T = 298K, R = 0.0821 atmL/mol K)

or, n = RT/PV = (0.0821 X 298)/(5.5 X 10) = 0.44 moles of He gas

Explanation:

Answer:

Two equal and opposite parallel forces not acting along the same line, form a couple. A couple is always needed to produce the rotation.

For example, turning a key in a lock and turning a steering wheel.

Answer:

The magnetic field through the wire must be changing

Explanation:

According to Faraday's law, the induced emf, ε in a metallic conductor is directly proportional to the rate of change of magnetic flux,Φ  through it. This is stated mathematically as ε = dΦ/dt.

Now for the wire, the magnetic flux through it is given by Φ = ABcosθ where A = cross-sectional area of wire, B = magnetic field and θ = angle between A and B.

So, dΦ/dt = dABcosθ/dt

Since A and B are constant,

dΦ/dt = ABdcosθ/dt = -(dθ/dt)ABsinθ

Since dθ/dt implies a change in the angle between A and B, since A is constant, it implies that B must be rotating.

So, for an electric current (or voltage) to be produced in the wire, the magnetic field must be rotating or changing.

Answer:

Option (b).

Explanation:

A star is a heavenly body which emits a tremendous amount of energy by the reaction of nuclear fusion.

Sun is the smallest star in the universe.

The star stars from the proto star, this is the process of birth of a star. Then it collapse due to the gravitational pull and then it tarts emit light and energy and become a star.

After the long long time, it starts to decay and become a neutron star or the black hole.

So, the correct option is (b).

Answer:

The rear wheels of a tractor are very wide so that the weight of the tractor spread over the greatest surface area possible ,so it doesnot sink into the soil.please as brainliest

Answer:

s=ut+at

its not the equation of motion..

Answer:

Average speed = 24 km/h

Explanation:

Given the following data;

Uniform speed A = 30 km/h

Uniform speed B = 20 km/h

To find the average speed;

Mathematically, the average speed of an object is given by the formula;

[tex] Average \; speed = \frac {total \; distance}{total \; time} [/tex] ..... equation 1

Total time = TA + TB

[tex] T_{A} = \frac {x}{30} [/tex]

[tex] T_{B} = \frac {x}{20} [/tex]

[tex] Total \; time = \frac {x}{30} + \frac {x}{20} [/tex]

[tex] Total \; time = \frac {5x}{60} [/tex]

Total distance = x + x

Total distance = 2x

Substituting the values into equation 1;

[tex] Average \; speed = \frac {2x}{\frac {5x}{60}} [/tex]

[tex] Average \; speed = \frac {2x*60}{5x} [/tex]

[tex] Average \; speed = \frac {120}{5} [/tex]

Average speed = 24 km/h

Answer:

mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

Explanation:

..........

Magnitude of acceleration

Explanation:

We know that acceleration can increase depending in the force applied on an object, any object with a greater mass will apply a greater force. F = M(a).

This Newton's second law establishes a relationship between the summary of the external force and the acceleration of the body,  It is demonstrated with the change in the direction and magnitude of the acceleration in the experiment

Newton's second law establishes a relationship between the net force and the acceleration, according to the expression

          ∑ F = m a

where ∑F is the sum of the external forces, m the mass and the acceleration of the body

In this case we have an initial situation, the block and a baking mass, therefore an acceleration is created towards the hanging mass given by

           W₁ = M₁ g

            F = ma

          M₁ g = m a

          a = [tex]\frac{M_1}{m} \ g[/tex]

where W₁ and M₁ are the weight and the masses of the mass of the body hanging under the acceleration of gravity.

In the second case, perhaps you have two masses, one on each side,

         ∑ F = W₁ -W₂

          ∑F = (M₁ -M₂) g

let's use Newton's second law

          (M₁ -M₂ ) g = m a

           a = [tex]\frac{M_1 - M_2}{m} \ g[/tex]

We can see that in the second case the acceleration depends on the difference of the hanging masses. This is a proof of Newton's second law where the effect on acceleration is due to the sum of all external forces and not of each force individually.

In conclusion with the realization of this experiment  demostrate the valid true of Newton's second law

Learn more about Newton's second law here:  https://brainly.com/question/19860811

Answer: B

Explanation: I think that it is B.

Answer:

This question is incomplete but the completed question is below

As a girl pushes an object across a wood floor, she suddenly comes to an area where the floor has been waxed recently, making it slippery. What becomes true of the coefficient of kinetic friction? A. The coefficient of kinetic friction increases. B. The coefficient of kinetic friction decreases. C. The coefficient of kinetic friction becomes zero. D. The coefficient of kinetic friction becomes negative.

The correct option is B

Explanation:

Coefficient of kinetic friction can be defined as the frictional force resisted by the motion of an object. From the question, it might take the girl to apply a force equivalent to just half that of the weight of the object to overcome friction to keep the object moving on a wood floor. Once she gets to the waxed area, the frictional force reduces, thereby also reducing the coefficient of kinetic friction further. Thus, she will be able to use less than half of the force (equivalent to less than half of the weight of the object) to push the object.

Thus, the correct option is B.

Answer:

shushhhgggvvv vgfxgh

Explanation:

gey laahhg

Answer:

it's a rule like water !!!!

Explanation:

Most importantly, time appears to run forward always never backwards. in other words there's perceived arrow of time and there's thermodynamic arrow of time, and they always point in a forward direction

for every system there are more states that seem chaotic then states that seem ordered.

the arrow of time seems to have something to do with that tendency. but to get from one instance to another where things get more entropy, we already need some kind of time, gotta admit that.

some (physicists) believe that time is an illusion, that the whole universe is already set in stone, like a block (the idea is therefore called block universe). from the perspective of a godlike outside observer the universe would be like a book, or a 4D movie. the characters might feel a movement of things in a direction, but rewinding it wouldn't feel different in any instance because the order in wich things happen is already written.

a different idea is that there are infinite many different futures and the further they are away, the less we can know for sure about them in a physical way. and this might also be work for the past, so that different parts could lead to one present.

when macroscopic information is deleted, it might not be reversible, so the past gets ultimately blurry. one example for deletion of macroscopic information this is the Library of Alexandria wich burned down.

all the quantum information is still conserved, but the order of things (like letters on pages) is lost and could have been in different configurations before. we can't ultimately not even see the past, as much as we would try.

personally the idea that the past is written in stone but the future is in flux doesn't make any sense for me. because than I could have free will now, but not from the perspective 10 days later.

the present would be a very special thing than, the stage where the universe likes to play.

maybe we can get a grasp on time if we look at it like rules for a game, like a cardboard game.

To get from one configuration to the next ,we must follow rules. like throwing dice and moving in monopoly.

gravity would be a simple real world example for such a rule, a natural law.

But no one would have a firm clue where this rules came from.

TLDR: I don't know and neither does anyone else for sure, not even top notch scientists.

the hardest questions are easy to formulate, but maybe even impossible for us to answer in a satisfying way. I hope we will understand those hard questions better one day, and maybe even get answers.

Answer:

A chemical change has taken place to form nitric oxide.

Answer:

1. atomic mass of silver 108

2. 18 electrons

3.an atom is the smallest particle of a substance that can exist by itself.

molecules are groups of atom

Explanation:

1. periodics table

2. gains electron, becomes negative

Answer:

To determine the atomic mass of silver, or any other element, add the number of protons and the number of neutrons together.

If a chlorine atom gains an electron, it will have an unequal number of protons and electrons, which makes it an ion. Because electrons are negatively charged, the ion will be negatively charged, also called an anion.

An atom is the smallest component of an element that retains all of the chemical properties of that element. A molecule is two or more atoms that have bonded together.

Protons and neutrons are found in the nucleus of an atom, while electrons are found in the area surrounding the nucleus of an atom. Protons have a positive charge, electrons have a negative charge, and neutrons have no charge.

Because the lithium atom loses a negatively charged electron, it becomes a positively charged ion, or cation. Because the fluorine gains a negatively charged electron, it becomes a negatively charged ion, or anion. A bond between an anion and a cation is an ionic bond.

Graphite and diamond look different because the carbon atoms bond to one another in different ways in the two minerals. This gives each mineral a unique lattice structure and, as a result, a different physical appearance.

Answer:

This has been explained below.

Explanation:

Sound waves move along the auditory canal and when moving they hit the tympanic membrane making it to vibrate. this vibration would make the 3 ossicles to move. the tympanic membrane is sticked to the auditory ossicles and the stapes are joined to the oval window. as movements occur in the oval window, there would be motions happening in the cochlea

Answer:

6. a. friction between a tire and the road

7. c. energy of motion

8. c. the force with which a moving vehicle hits another object

Explanation:

6. As a car moves along the road, the tires push back against the ground. As tires push back against the ground, the road exerts and opposing force to the motion of the tires. This opposing force is the friction between the tires and the road. This opposing force between the tires and the rad is called traction.

So, the answer is a

7. As an object moves, it has energy. This energy due to its motion is called kinetic energy.

So, the answer is c

8. When a moving vehicle hits another object, it exerts a force on the object. The process of the vehicle hitting the other object is called impact and the force exerted on the object is called the force of impact.

So, the answer is c.

Answer:

"the plants had already started growing."

Explanation:

I think this is the answer because the definition of a dependent variable is the variable that is being affected by the change. Since the plants had already started growing BECAUSE of "They ran out of the farmer's compost, so

some of the plants received that compost

when the seeds were planted and other

plants got hardware store compost after

the plants had already started growing."

Sorry if I am wrong, I am just a 4th grader, pls don't hate on me, I am just trying to help :)

Answer:

It's compost

Explanation:

In case you needed the dependent variable, its the amount of plant growth

Answer:

nuclear fusion

Explain: that's just my best term.

Answer:

A

Explanation:

Nuclear Fusion

Answer:

a. i. 6.608 V ii. 5.507 V iii. 1.89 V iv. 1.89 V

b. i. 0.22 mJ ii. 0.182 mJ iii. 0.027 mJ iv. 0.036 mJ

Explanation:

a. The voltage across each capacitor

Since the 15 μf and 20 μf capacitors are in parallel, their total capacitance is C = 15 μf + 20 μf = 35 μf.

Also, since C is in series with the 10 μf and 12 μf which are in series, their total capacitance, C' is gotten from 1/C' = 1/10 μf + 1/12 μf + 1/35 μf  

1/C' = (12 + 42 + 35)/420 /μf

1/C' = 89/420 /μf

C' = 420/89 μf

C' = 4.72 μf

The total charge in the circuit' is thus Q = C'V where V = voltage = 14 V

So, Q = C'V =  4.72 μf × 14 V = 66.08 μC

Since the 10 μf and 12 μf are in series, Q is the charge flowing through them.

Since Q = CV and V = Q/C

i. The voltage across the 10 capacitor is

V = 66.08 μC/10 μF = 6.608 V

ii. The voltage across the 12 capacitor is

V = 66.08 μC/12 μF = 5.507 V

The voltage across the 15 μF and 20 μF capacitors.

Since the capacitors are in parallel, the voltage across them is the voltage across their combined capacitance, C

So, V = Q/C = 66.08 μC/35 μF = 1.89 V

iii. The voltage across the 15 μF capacitor is 1.89 V

iv. The voltage across the 20 μF capacitor is 1.89 V

b. The potential energy of each capacitor

i. The potential energy of the 10 μF capacitor

E = 1/2CV² where C = Capacitance = 10 μF = 10 × 10⁻⁶ F and V = voltage across capacitor = 6.608 V

E = 1/2CV²

E = 1/2 × 10 × 10⁻⁶ F(6.608 V)²

E = 5 × 10⁻⁶ F(43.666) V²

E = 218.33 × 10⁻⁶ J

E = 0.21833 × 10⁻³ J

E = 0.21833 mJ

E ≅ 0.22 mJ

ii. The potential energy of the 12 μF capacitor

E = 1/2CV² where C = Capacitance = 12 μF = 12 × 10⁻⁶ F and V = voltage across capacitor = 5.507 V

E = 1/2CV²

E = 1/2 × 12 × 10⁻⁶ F(5.507 V)²

E = 6 × 10⁻⁶ F(30.327) V²

E = 181.96 × 10⁻⁶ J

E = 0.18196 × 10⁻³ J

E = 0.18196 mJ

E ≅ 0.182 mJ

iii. The potential energy of the 15 μF capacitor

E = 1/2CV² where C = Capacitance = 15 μF = 15 × 10⁻⁶ F and V = voltage across capacitor = 1.89 V

E = 1/2CV²

E = 1/2 × 15 × 10⁻⁶ F(1.89 V)²

E = 7.5 × 10⁻⁶ F(3.5721) V²

E = 26.79 × 10⁻⁶ J

E = 0.02679 × 10⁻³ J

E = 0.02679 mJ

E ≅ 0.027 mJ

iv. The potential energy of the 15 μF capacitor

E = 1/2CV² where C = Capacitance = 20 μF = 15 × 10⁻⁶ F and V = voltage across capacitor = 1.89 V

E = 1/2CV²

E = 1/2 × 20 × 10⁻⁶ F(1.89 V)²

E = 10 × 10⁻⁶ F(3.5721) V²

E = 35.721 × 10⁻⁶ J

E = 0.035721 × 10⁻³ J

E = 0.035721 mJ

E ≅ 0.036 mJ

Answer:

displacement

Explanation:

I hope ans will be right

Answer:

n sei

Explanation:

n seei

Answer:

i relly need help with points it  whould help if you make me brainliest

Explanation:

The answer would be B..

Since sand can heat up quickly, it will also cool off quickly. But water takes a long time to heat up and cool down.

Answer:

F = 3.6 kN, direction is 9.6º to the North - East

Explanation:

The force is a vector, so one method to find the solution is to work with the components of the vector as scalars and then construct the resulting vector.

Let's use trigonometry to find the component of the forces, let's use a reference frame where the x-axis coincides with the East and the y-axis coincides with the North.

Wind

X axis

          F₁ = 2.50 kN

Tide

         cos 30 = F₂ₓ / F₂

         sin 30 = F_{2y} / F₂

          F₂ₓ = F₂ cos 30

         F_{2y} = F₂ sin 30

         F₂ₓ = 1.20cos 30 = 1.039 kN

         F_{2y} = 1.20 sin 30 = 0.600 kN

the resultant force is

X axis

        Fₓ = F₁ₓ + F₂ₓ

        Fₓ = 2.50 +1.039

        Fₓ = 3,539 kN

        F_y = F_{2y}

        F_y = 0.600

to find the vector we use the Pythagorean theorem

         F = [tex]\sqrt{F_x^2 +F_y^2}[/tex]

         F = [tex]\sqrt{ 3.539^2 + 0.600^2 }[/tex]

         F = 3,589 kN

the address is

         tan θ = F_y / Fₓ

         θ = tan⁻¹ [tex]\frac{F_y}{F_x}[/tex]

         θ = tan⁻¹  [tex]\frac{0.6}{3.539}[/tex]0.6 / 3.539

         θ = 9.6º

the resultant force to two significant figures is

         F = 3.6 kN

the direction is 9.6º to the North - East

Complete question is;

A cylinder of compressed gas is at a temperature of 23°C. It is cooled until it reaches the pressure of 2000kPa. It has to be cooled to 90K before this happens. Calculate the starting pressure of the gas

Answer:

Starting pressure = 604 KPa

Explanation:

We are given;

Initial temperature; T1 =23°C = 298 K

Final temperature; T2 = 90 K

Final pressure; P2 = 2000 KPa

From gay lussac's law, we know that;

P1•T1 = P2•T2

P1 = (P2•T2)/T1

P1 = (2000 × 90)/298

P1 ≈ 604 KPa