Pretest: Waves
18
Select the correct answer.
Which type of wall would make the best soundproofing for room?
OA.
1.0 centimeter thick glass
OB.
two layers of 0.5 centimeter thick glass with 0.5 centimeters of air between them
OC.
two layers of 0.5 centimeter thick glass with 0.3 centimeters of vacuum between them
OD.
1.0 centimeter thick steel

Answers

Answer 1
Definitely the one with a vacuum on the middle as sound does not travel through a vacuum.

Related Questions


An object is dropped from rest.
Calculate its velocity after 2.5 seconds

Answers

Velocity = 9.8 x 2.5 = .... m/s

ILL GIVE BRAINLY THING


Tom has been hired to deliver 11 m3 of sand. If the truck that Tom is driving has a truck bed that is 2.5 m X 1.6 m, X 0.75 m how many trips will Tom need to complete the order?


PLS GO TO MY PROFILE TO SEE THE OTHER QUESTIONS I POSTED I GIVE BRAINLY THING FOR THOSE AS WELL THANK YOU

Answers

Answer:

About 3 trips

Explanation: if we do 2.5m*1.6m*0.75 it equals to 11000 then we divide that to 11m3 and it gives you 3.6 so it will be about 3 times

Thx

PLZ HELP DUE IN 5MINUTES

Answers

I think nitrogen as it is the major component

Answer:

Nitrogen is de solvent while others are the solute

can the answer to density be simplified​

Answers

Answer: yes because all densities can be simplifed it just depends on the number.

PLEASE HELP!!!
If the potential difference across a 30.0-ohm resistor is 10.0 volts, what is the current through the resistor?

Answers

V(voltage) = I(current)R(resistance)
we can convert this to I = V/R
now just substitute

I = 10/30
I = 1/3 or 0.33

current = 0.33

What does the kinetic theory explain?


Heat is due to temperature.


Heat is due to potential energy.


Heat is due to the motion of molecules.


Heat is due to Pascal´s principle.

Answers

Heat is due to the motion of molecules

Your answer would be option 3/C

Heat is due to the motion of molecules.

plz answer this very soon

Answers

Answer:

Im gonna say it is answer A:) Hope this helps!

Explanation:

Answer the following:
You are going to race your friend to a tree near the back of the playground. The tree is 24 meters away from where you stand. It will take you 4 seconds to reach the tree. What will your average speed be?

Answers

Answer:

1. 6 m/s.

2. 320 miles.

Explanation:

1. Determination of the average speed.

Total distance travelled (D) = 24 m

Total time (t) = 4 s

Average speed =.?

Average speed is simply defined:

Average speed = Total distance /total time

Average speed = 24/4

Average speed = 6 m/s

2. Determination of the distance travelled by the train.

Speed = 40 mph

Time = 8 h

Distance =?

Speed is simply defined as:

Speed = Distance /time

40 = Distance / 8

Cross multiply

Distance = 40 × 8

Distance = 320 miles

Therefore, the train travels a distance of 320 miles.

!PLEASE HELP PLEASE!Why is wax the same suspense when it melts from a candle?
(Even though wax melts from a candle, it is still the same substance. Why is that?)

Answers

Answer:

it is the same substance because it didn't change the process of that it was it just changed its state for would to liquid

At which point(s) does the ball have 25% potential energy and 75% kinetic energy?*

Answers

Answer:

hey

Explanation:

hey

A person throws a baseball from height of 7 feet with an initial vertical velocity of 50 feet per second. Use the vertical motion model, h = -16t2 + v … t +s, where y is the initial velocity in feet per second and s is the height in feet, to calculate the amount of time the baseball is in the air before it hits the ground.

Answers

Answer:

t = 3.25 seconds.

Explanation:

A person throws a baseball from a height of 7 feet with an initial vertical velocity of 50 feet per second is given by :

[tex]h=-16t^2+vt+h_0[/tex]

[tex]h=-16t^2+50t+7[/tex]

We need to find the amount of time the baseball is in the air before it hits the ground. ATQ,

h = 0

[tex]-16t^2+50t+7=0\\\\t=\dfrac{-50 \pm \sqrt{50^2-4\times (-16)(7)} }{2(-16)}\\\\t=\dfrac{-50 + \sqrt{50^2-4\times (-16)(7)} }{2(-16)}, \dfrac{-50- \sqrt{50^2-4\times (-16)(7)} }{2(-16)}\\\\t=-0.134\ s,3.25\ s[/tex]

Neglecting negative value, t = 3.25 s

So, the baseball will hit the ground at t = 3.25 seconds.

1. who was john locke?
2. what were his 3 big ideas?

3. what does each of his 3 big ideas mean?

Answers

1.John Locke is an English physician one or the most influential thinkers and commonly known as the “Father of Liberalism”


2.Three big ideas were life,liberty, and property



3.They were social contract they helped people in order to protect their rights. He believed all people should have the right to life, liberty and the right to own property.

name six kinds of simple machines.

Answers

Answer:

the wheel and axle, the lever, the inclined plane, the pulley, the screw, and the wedge

Explanation:

The wheel, Axel, Lever, Inclined Pane, pulley, screw, and wedge!

two same size anvils are dropped from different heights. Assume both anvils are made of the same material (iron) and there is no air resistance. Which anvil has the greatest acceleration during the fall? ​

Answers

Everything falls at the same rate.

i’m stuck on this problem, help is very appreciated!!

Answers

Explanation:

Use the equation F=m×a

F= 1500 N

M= 500kg

a= F/M

a= 1500÷ 500

a= 3m/s^2

Answer:

Explanation:

Force, f = 1500 N

Mass, m = 500 kg

Acceleration, a = ?

f = ma

a = f/m

= 1500 / 500 = 3m/s^2

Hope this helps

plz mark as brainliest!!!!!

why does nobody love me?

Answers

Answer: I’m sure theirs people out there that like you, and if there isn’t, you should just focus on yourself.

Explanation:

Answer:

Well, There are a couple reasons it could seem like nobody loves you...

Explanation:

One reason is that people really do love you, they just were never shown love and affection so they are unsure of how to show that to you. Another reason could be that it's god telling you that you are meant for much bigger and greater things. Maybe it's him reminding you that, yeah, people really suck, but that's life, and you're better than that. If you make the right decisions in life, you will be able to stand taller than they ever did. I hope this helps.. : )

Which of the following statements best describes why the mass of a bowling ball would not change if it were transported from Earth to the Moon?
Gravity is a constant force
The bowling ball wil adapt to the changes in gravity
Matter is resistant to acceleration and changes in gravity
The amount of matter in the bowling all remains the same

Answers

Answer:

D hope this helps

Explanation:

Answer:

D

Explanation:

The amount of matter in the bowling ball remains the same.

PLEASE HELP!!!! ILL MARK BRAINLYEST!!

A change in the size or shape of a substance is a _________ change

A. chemical
B. physical
C. material
D. nuclear

Answers

The answer will be B

PLSSS HELP ITS URGENT ILL RATE YOU BRAINLIEST:) A truck whose bed is 4 m long, 2.2 m wide, and 1.0 m high is delivering sand for a sand-sculpture competition. About how many trips must the truck make to deliver 23 m^3 of sand?

Answers

Answer:

one truck load is 2.5*1.5*1 = 3.75m^3

7/3.75 = 1.86 loads,

so 2 trips must be made.

Explanation:

To see how deep a well is you drop a rock in. The rock hits the water 10 seconds later.
How deep is the well? Draw the velocity-time graph for this motion.

Answers

Answer:

490m

Explanation:

Given parameters:

     Time taken = 10s

Unknown:

Depth of the well = ?

Solution:

To find the depth of the well, we apply the appropriate motion equation:

     h = ut + [tex]\frac{1}{2}[/tex]gt²

h is the depth

u is the initial velocity

g is the acceleration due to gravity  = 9.8m/s²

t is the time taken

 Input the parameters and solve;

 The ball was dropped from rest; u = 0

      h  =  [tex]\frac{1}{2}[/tex]gt²

      h  =   [tex]\frac{1}{2}[/tex] x 9.8 x 10²  = 490m

An object is thrown horizontally off of a cliff. While falling, what happens to the horizontal acceleration?
It first decreases and then increases
O It decreases
O It increases
O It stays at zero
O It stays at a constant, non-zero, value

Answers

There is no acceleration in the horizontal direction because the speed in that direction is constant. So it stays at zero.

What does the color of a star indicate

Answers

Answer:

Its temperature

Explanation:

Answer:

The stars age

Explanation:

As stars age, they run out of hydrogen to burn, decreasing the amount of energy they give off. So the younger stars can look bluer while older ones look more red.

Hope this helps :3

Which of the following is a molecule? *
1.He
2.Be
3.NO
4.Na

Answers

No. 3( NO) is the molecule

1. In general
, which type of compound tends to have the lowest melting point?
O A. Molecular solids
O B. Network solids
O C. lonic salts
O D. Metals

Answers

Your answer will be molecular solids

does changing position of charges change the magnitude

Answers

Answer:

No, they will not change.

Explanation:

Kinetic and potential energy are forms of what kind of energy?

gravitational

chemical

electrical

mechanical

Answers

Answer:

mechanical energy

Explanation:

The key difference that exists between kinetic energy and potential energy lies in the fact that, potential energy is that form of mechanical energy which is stored within an object, ready to be released as and when needed to do some work, while, kinetic energy is that form of mechanical energy that has been released and is associated with the body in motion.

A car on flat ground accelerates at 0.785 m/s2 when a net force of 1050 N acts on it. How much normal force acts on it?

Answers

Answer:

13108.3N

Explanation:

Given parameters:

Acceleration = 0.785m/s²

Net force  = 1050N

Unknown:

Normal force acting on car  = ?

Solution:

The normal force on this car is the weight of the car;

   Normal force  = mg

where m is the mass of the car

           g is the acceleration due to gravity = 9.8m/s²

Now solve for the mass;

             Net force  = mass x acceleration

                1050  = mass x 0.785

                 mass  = [tex]\frac{1050}{0.785}[/tex]   = 1337.6kg

So,

     Normal force  = 1337.6kg x 9.8m/s² = 13108.3N

13108 works as well for acellus

F all of the energy in a falling object's gravitational potential energy store is transferred to its kinetic energy store by the time it lands, then the relationship shown below can be used. Which of the four options below it correctly shows how this relationship can be expressed in terms of height, h?

Answers

Answer:

The options are not shown, so let's derive the relationship.

For an object that is at a height H above the ground, and is not moving, the potential energy will be:

U = m*g*H

where m is the mass of the object, and g is the gravitational acceleration.

Now, the kinetic energy of an object can be written as:

K = (1/2)*m*v^2

where v is the velocity.

Now, when we drop the object, the potential energy begins to transform into kinetic energy, and by the conservation of the energy, by the moment that H is equal to zero (So the potential energy is zero) all the initial potential energy must now be converted into kinetic energy.

Uinitial = Kfinal.

m*g*H = (1/2)*m*v^2

v^2 = 2*g*H

v = √(2*g*H)

So we expressed the final velocity (the velocity at which the object impacts the ground) in terms of the height, H.

What is the method of charging called?

Answers

The answer is conduction

Consider a double Atwood machine constructed as follows: A mass 4m is suspended from a string that passes over a massless pulley on frictionless bearings. The other end of this string supports a second similar pulley, over which passes a second string supporting a mass of 3m at one end and m at the other. Using two suitable generalized coordinates, set up the Lagrangian and use the Lagrange equations to find the acceleration of the mass 4m when the system is released. Explain why the top pulley rotates even though it carries equal weights on each side.​

Answers

Can you apply the picture to the problem for us
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