Sound is repeated near hills.​why

Answers

Answer 1

Answer:

Sound waves are reflected back


Related Questions

How does a wheel and axle make work easier?

Answers

The wheel and axle is a simple machine that reduces the friction involved in moving an object, making the object easier to transport. ... Once the object is moving, the force of friction opposes the force exerted on the object. The wheel and axle makes this easier by reducing the friction involved in moving an object.

In addition to reducing friction, a wheel and axle can also serve as a force multiplier, according to Science Quest from Wiley. If a wheel is attached to an axle, and a force is used to turn the wheel, the rotational force, or torque, on the axle is much greater than the force applied to the rim of the wheel.

If the mass of an object increases, then its kinetic energy will ____________ because __________________________

Answers

Answer:

when mass will increase then kinetic energy will also increase because both have positive relationship

Explanation:

when volume increase then molecule come closer then more movement will occurs and kinetic energy increase

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Which option identifies the importance of Snow’s scientific work to the medical community?


It was the foundation for epidemiology.

It pioneered the invention of vaccines.

It was the foundation for germ theory.

It created sterilization techniques.

Prior to germ theory, how were diseases thought to be transmitted?


human contact

animal contact

poisonous air

spoiled food

Answers

Answer:

It founded the foundation for epidemiology Human contact

The answer are:

1. It founded the foundation for epidemiology.2. poisonous air

Intensitatea curentului electric a unui circuit este de 123A iar sarcina electrica este de 1,7C sa se afle intervalul de timp in care este transportata sarcina electrica

Answers

The intensity of the electric current of a circuit is 123A and the electric charge is 1.7C to find the time interval in which the electric charge is transported.

Given that,

Current, I = 123 A

Electric charge, q = 1.7 C

To find,

The time interval in which the charge is transported.

Solution,

The electric current is given by electric charge per unit time. So,

[tex]I=\dfrac{q}{t}\\\\t=\dfrac{q}{I}\\\\t=\dfrac{1.7}{123}\\\\t=0.0138\ s[/tex]

So, the required time is 0.0138 seconds.

What nuclear reaction is shown in the equation below?
A. Nuclear fusion
B. Nuclear fission
C. Positron emission
D. Beta decay​

Answers

The carbon isotope was cobined with the proton to produce the nitrogen isotope hence it is a fusion reaction.

What is a nuclear fusion?

The term nuclear fusion refers to a kind of reaction in which two nuclei fuse together to give rise to a single nuclei with the evolution of energy.

We can see that the carbon isotope was cobined with the proton to produce the nitrogen isotope hence it is a fusion reaction.

Learn more about nuclear fusion:https://brainly.com/question/12701636

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Answer:

A. Nuclear fusion

Explanation:

got it right, trust

Picking up a puppy is easy, but picking up a large horse is difficult. *

1st law
2nd law
3rd law

Answers

Answer:

1st

Explanation:

It is because the horse is heavier

When a cyclist is decelerating uphill the forces on him are balanced or unbalanced ​

Answers

Answer:

Unbalanced

Explanation:

A cyclist decelerating uphill has unbalanced forces acting on him. An unbalanced force acting on a body has a net force which is greater than zero. When a body is accelerating or decelerating, the forces are not balanced.

A body with a net force of zero has balanced forces acting on it. Such body is moving with constant acceleration. According to newton's first law of motion" a body will remain in state of rest or of uniform motion unless an external force acts on it". The external force causes acceleration to change drastically.

ANSWER QUICK 30 POINTS
What force controls the movement of the planets around the sun, holds together stars grouped in galaxies, and galaxies grouped in clusters? Thoroughly explain your answer, making sure to include an example and describe how this force keeps planets in orbit. Make sure to write at least 3-5 sentences and proper conventions (spelling, grammar, punctuation, etc.) to respond. Put all answers in your own words

Answers

Answer:

Gravity controls the movement of the planets around the sun, holds together stars grouped in galaxies, and galaxies grouped in clusters.  The Universal Law of Gravitation depends on two things.  First it depends on mass of each object  and the second factor is the distance between two objects.  If the mass of one object is Larger, the gravitational pull towards it will be larger  and the smaller distance, the larger the gravitational pull will be between the objects. Therefore the Larger planets have more moon and the inner planets have less.

Explanation:

What does ionic bond mean

Answers

Answer:

The acception and donation of elections within two elements is called as ionic bond.

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A friend tells you that objects with more mass fall faster because they
have a stronger gravitational pull to Earth. How can you show your friend
that this is not true?

Answers

Answer:

by throwing heavy mass and less mass in vacuum simultaneously.

On Earth, a spring stretches by 5.0 cm when a mass of 3.0 kg is suspended from one end.
The gravitational field strength on the Moon is
1/6 of that on Earth.
Which mass, on the Moon, would stretch the spring by the same extension?

Reasons too :(
igcse physics

Answers

Answer:

Mass = 18.0 kg

Explanation:

From Hooke's law,

F = ke

where: F is the force, k is the spring constant and e is the extension.

But, F = mg

So that,

mg = ke

On the Earth, let the gravitational force be 10 m/[tex]s^{2}[/tex].

3.0 x 10 = k x 5.0

30 = 5k

⇒ k = [tex]\frac{30}{5}[/tex] ................ 1

On the Moon, the gravitational force is [tex]\frac{1}{6}[/tex] of that on the Earth.

m x [tex]\frac{10}{6}[/tex] = k x 5.0

[tex]\frac{10m}{6}[/tex] = 5k

⇒ k = [tex]\frac{10m}{30}[/tex] ............. 2

Equating 1 and 2, we have;

[tex]\frac{30}{5}[/tex]  = [tex]\frac{10m}{30}[/tex]

m = [tex]\frac{900}{50}[/tex]

    = 18.0

m = 18.0 kg

The mass required to produce the same extension on the Moon is 18 kg.

Answer:

18 kg

Explanation:

weight (N) = mass (kg) × gravitational acceleration (m/s²)force (N) = k (spring constant) × extension (m)

On Earth, acceleration of gravity is 10 m/s²

weight = 3.0 (kg) × 10 (m/s²)weight = 30 (N)

Since weight is a force, the force is 30 N. The value of spring constant is unknown

30 (N) = k × 5 (m)k = 6 (m/N)

Spring constant is 6. Now let's find the mass on the Moon

mass (kg) × gravitational acceleration (m/s²) = k (spring constant) × extension (m)

Gravitational acceleration of the moon is 1/6 of that on Earth. Earth's g = 10, so Moon's g = 10/6

m × 10/6 = 6 × 5m = 30/(10/6)m = 18

The mass is 18 kg

Write a message to Mr. Chang explaining why the groundwater heating system will warm the school more than the water heater system. Use evidence to support your claim. For each piece of evidence you use, explain how the evidence supports your claim.

Answers

Answer:

For, heating purposes more the quantity of  water more will be the heating. Clearly, underground heating would have more water and hence, it will have edge over the  water heater system.

Moreover, for things at the same temperature, the thing with more molecules has more total kinetic energy (thermal energy) than the thing with fewer molecules. The groundwater heating system uses heat from the heat stored naturally in groundwater or aquifers. Thus, saving the cost of power required to heat in normal water heater.

Explanation:

The groundwater heating system will warm the school more than the water heater system due to the fact that it uses more water more than the other system.

Based on the complete question, it should be noted that the addition of energy leads to an increase in motion which results in the rise in temperature.

The groundwater heating system will warm the school more than the water heater system due to the fact that it uses more water more than the other system even though its water isn't as warm as in the other system.

Read related link on:

https://brainly.com/question/20116115

This is very hard, I don't understand.

Answers

Answer:

[tex]4x - 6 = 90 \\ 4x = 96 \\ \boxed{x = 24}[/tex]

Now, AD is an altitude of∆ABC

Therefore, D is the midpoint of BC

[tex]x + 7 = 2x - 15 \\ \boxed{x = 22}[/tex]

CD is (22+7) = 29 & DB is (2×22-15) = 29

[tex] \huge \boxed{\: x = 24 }\\ \huge \boxed{CD \: and \:DB= 29}[/tex]

Which of the following quantities are vectors?
charges
electric fields
energy
potentials

Answers

Answer:

electric fields

Explanation:

PLEASE HELP ASAP!!!!!
Carrie pulls a 41.5 kg bin across the floor of her garage using a rope that is attached to the bin. She pulls with a force of 138 N, at an angle of 28.0° above horizontal. The coefficient of kinetic friction between the floor and the box is 0.290 . What is the acceleration of the box?

Answers

Answer: 0.81N

Explanation: Fwx = .165x 9.81 Silicon 30 = 0.81N

Puck 1 is moving 10 m/s to the left and puck 2 is moving 8 m/s to the right. They have the same mass, m.



a. What is the total momentum of the system before the collision? (Answer in terms of the mass, m.) (0.5 points)





b. What is the total momentum of the system after the collision? (Answer in terms of the mass, m.) (0.5 points)





c. Write puck 1's velocity after the collision in component form. (1 point)







d. What is the y-component of puck 2's velocity after the collision? (1 point)







e. What is the x-component of puck 2's velocity after the collision? (1 point)







f. At what angle does puck 2 move after the collision? Determine the angle and draw it on the diagram. (1 point)







g. What is the magnitude of puck 2's velocity after the collision? (1 point)

Answers

Answer:

(a) the total momentum of the system before the collision = -2m kg.m/s.

(b) the total momentum of the system after the collision = -2m kg.m/s.

(c) puck 1's velocity after the collision in component form = (5.44 i, 2.54 j)

Explanation:

Given;

mass of Puck 1 , = m

mass of Puck 2, = m (since they have the same mass m)

initial velocity of Puck 1, u₁ = 10 m/s to the left

initial velocity of Puck 2, u₂  = 8 m/s to the right

Let the rightward direction be positive direction

Let the leftward direction be negative direction

(a) the total momentum of the system before the collision;

P₁ = (initial momentum of Pluck 1) + (initial momentum of Pluck 2)

P₁ = (-mu₁) + mu₂

P₁ = mu₂ - mu₁

P₁ = m(u₂ - u₁)

P₁  = m(8 - 10)

P₁  = -2m kg.m/s

(b) the total momentum of the system after the collision;

Based on the principle of conservation of linear momentum, the total momentum before collision is equal to the total momentum after collision.

Thus, the total momentum of the system after the collision is -2m kg.m/s.

(c) puck 1's velocity after the collision in component form

[tex]v = (v_x, v_y)\\\\v = (vcos \theta , vsin \theta)\\\\v = (6cos 25^0 , 6sin25^0)\\\\v = (5.44i, 2.54j)m/s[/tex]

If you put something like a piece of cardboard between a magnet and an iron nail, the magnet still holds the nail in place, even though the magnet is not touching the nail. Explain how that happens. Use the word induce in your response.

Answers

Answer:

A magnet has a field having lines of force around it that moves through the air which is a nonpermeable medium that allows the passage of magnetic field lines of force. The cardboard is a similar nonpermeable medium and the magnetic lines of force pass through to induce magnetism in the iron nail which is a ferromagnetic material that becomes magnetized by the magnetic field from the magnet

The induced magnetism in the iron nails causes the reverse poles to form in the iron with the iron domain's induced north pole pointing in the direction of the south pole of the magnet and vice versa

The iron nail is then attracted to the magnet as like poles attract, thereby holding the iron nail in place with the cardboard in between, without direct contact between the nail and the magnet as the cardboard prevents the magnet from touching the iron nail held in place

Explanation:

What is the speed of a person travelling 30 meters in 5 seconds?

Answers

Answer:

[tex]6\:\mathrm{m/s}[/tex]

Explanation:

Denote average speed by [tex]S=\frac{d}{t}[/tex] where [tex]d[/tex] is total distance travelled and [tex]t[/tex] is time.

Plugging in given values, we get:

[tex]S=\frac{30}{5}=\fbox{$6\:\mathrm{m/s}$}[/tex].

Answer:

s

Explanation:

IS IT B!! if not pls helpp!

Answers

Answer:

I believe you are correct but we just started this unit

Explanation:

What 2 factors impact gravitational pull?

mass and distance

matter and energy

size and shape

speed and direction

Answers

Answer:

When dealing with the force of gravity between two objects, there are only two things that are important – mass, and distance. The force of gravity depends directly upon the masses of the two objects, and inversely on the square of the distance between them

How does attachment affect exploration? Be sure to include findings from both Harlow and Ainsworth in your response.

Answers

“The monkey became attached to the cloth mother so it developed a sense of security. ... In both Ainsworth and Harlow's studies it goes to show that a child social development is dependent on the attachment of a caregiver or mother.”

Answer:

Attachment can affect many things. When you go back to the experiment, you see that they are testing 4 monkeys. They want to see if they would go to the cloth mother or the wire mother. But that is just the base of the experiment. Once the monkeys pick the mother, they have attached themselves to the mother, because animals will pick what is mother, because once you are born, the "hunger games" begin in the wild. They will stay by their mother's side until they are grown and ready to go on their own. When you think about this whole experiment, you know that this experiment was designed as a test of the relative importance of contact comfort. They could have picked any animal for this, and the outcome would have been very similar because as a baby you need to find things that you trust and that is your mother.

Explanation:

Select the correct answer.
A stone is dropped from a tower 100 meters above the ground. The stone falls past ground level and into a well. It hits the water at the bottom
of the well 5.00 seconds after being dropped from the tower. Calculate the depth of the well. Glven: g=-9.81 meters/second?
A.22.5 meters
B.50.7 meters
C.100 meters
D.110 meters
E.152.45 meters

Answers

Answer:

A

Explanation:

Givens

d = 100 meters plus the depth of the well

d = 100 + x                          where x is the depth of the well.

vi = 0 m/s                           The object is dropped. It was not thrown.

t = 5 seconds

a = 9.81 m/s^2

formula

d = vi*t  +  1/2 a t^2

solution

100 + x = 0 + 1/2 * 9.81 * 5^2

100 + x = 122.625             Subtract 100 from both sides

x = 122.625 - 100

x = 22.6  m

The well is 22.6 meters deep.

A ball is thrown with 50J of kinetic energy, it hits a target which moves with 30J of kinetic energy, how much energy goes to the thermal store of the surroundings?

Answers

Answer:

The energy that will go will for thermal store of the surroundings is 20 J.

Explanation:

Given;

kinetic of the thrown ball, K.E₁ = 50 J

kinetic energy used to move the target, K.E₂ = 30 J

The excess energy that will go will for thermal store of the surroundings;

ΔK.E = K.E₁ - K.E₂

ΔK.E = 50J - 30J

ΔK.E = 20 J

Therefore, the energy that will go will for thermal store of the surroundings is 20 J.

how is velocity ratio of wheel and axle calculatedaad

Answers

Answer:

VR = [tex]\frac{Radius of wheel}{Radius of axle}[/tex]

Explanation:

A machine is a device that can be used to overcome a load by the application of an effort through a pivot. Examples are: pulleys, wedge, screw jack, wheel and axle etc.

The wheel and axle is a simple device that can be used to lift a load through a height. Its velocity ratio (VR) can be determined by:

VR = [tex]\frac{Radius of wheel}{Radius of axle}[/tex]

Note that for a practical wheel and axle, the radius of the wheel is greater than the radius of the axle.

Who is the father of Nuclear Physics?​

Answers

Answer:

Ernest Rutherford, 1st Baron Rutherford of Nelson

A body with mass 2 kg absorbs heat 418.4J when its temperature raises from 293K to 343K . What is the specific heat of the body?

Answers

Answer:

C M (change in T) = heat absorbed      thermal equation for heat gained

C = 418.4 J / (2 kg * 50 deg K) = 4.184 J / kg * deg K     specific heat

Note: 1 gm =.001 kg

So C = .004184J / gm * deg K

Also, 1 J = .239 cal   so in conventional terms

C = .001 cal / gm deg K     (very low, water would be 1 cal / gm deg C


In the diagram shown above, the circles represent small balls that have
electric charges. Ball 1 has a negative charge, and ball 2 is repelled by ball 1
Next, you see that ball 2 repels ball 3 and that ball 3 attracts ball 4. What is
the electric charge on ball 4?
Ball 4 may have either a positive or negative charge,
Ball 4 has a negative charge.
Ball 4 has a positive charge.

Answers

I think the answer is Bell 4 may have either a positive or neg

Answer:

ball 4 has a positve charge

Explanation:

-Ball 2: is negative because it is repelled by ball one (like signs repel)

- ball 3: is also negative because it is repelled by ball one (like signs repel)

- Ball 4: is positive because it is attracted by ball 3 (opposite signes attract)

The answer to a multiplication problem is called the?

Answers

Answer:

product

Explanation:

Answer:

product

Explanation:

You find the product when you multiply two or any number of factors.

A 10.0kg box sits at rest on ramp that has an incline of 20.0° from the horizontal. What is the force of gravity acting on the box?

A. -98.0N

B. 98.0N

C. -92.1N

D. -33.5N

Answers

I think it would be d

Answer:

98.0N

Explanation:

what are the three laws of motion and examples​

Answers

Explanation:

In Newton's 1 law, an object will not change its motion unless a force acts on it.

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. 

In Newton's 2 law, the force on an object is equal to its mass times its acceleration.

Riding your bicycle is a good example of this law of motion at work. ... Your leg muscles pushing pushing on the pedals of your bicycle is the force. When you push on the pedals, your bicycle accelerates.

In Newton's 3 law, when two objects interact, they apply forces to each other of equal magnitude and opposite direction.

For example, when you jump, your legs apply a force to the ground, and the ground applies and equal and opposite reaction force that propels you into the air.

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