If a train is 100 km away, how much sooner would you hear the train coming by listening to the rails (iron) as opposed to listening for it standing by the track? In other words, how much faster will the sound travel through the iron rails than through the air? Assume the air temperature is 0°C.Sound will reach you ______ seconds sooner.

302

324

280

Answers

Answer 1
Answer:
Wellll . . . it's doubtful that you'd hear the sound of a train
from 100 km away (about 62 miles), but this is a fun problem
so let's go through it just for the math.

Online, I looked up the speed of sound in various materials.
Here's what I found:

-- Speed of sound in normal air . . . . .  343 m/s

-- Speed of sound in iron . . . . . 5,130 m/s 

But let's go a little farther !
Rails used to be made of cast iron or wrought iron. 
But now they're made of hot rolled steel.

-- Speed of sound in steel . . . . . 6,100 m/s

     Time to cover the distance = (distance) / (speed)

         Time through air  =  (100,000 m) / (343 m/s)

                                       =  291.5 sec  =  4 minutes 51.5 seconds

 Time through old iron rails  =  (100,000 m) / (5,130 m/s)

                                               =   19.5 seconds    (272 sec sooner)

 Time through new steel rails = (100,000 m) / (6,100 m/s)

                                                 =   16.4 seconds   (275 sec sooner)

Answer 2
Answer:

Final answer:

The speed of sound varies in different mediums. In Physics, the speed of sound in air at 0°C is about 331.5 m/s, while in iron it's about 5130 m/s. If a train is 100 km away, the sound travelling through the iron rails would reach you approximately 282 seconds sooner than the sound through the air.

Explanation:

In Physics, the speed at which sound travels depends on the medium through which it's travelling. The speed of sound in air at 0°C is approximately 331.5 m/s. On the other hand, the speed of sound in iron is about 5130 m/s.

To determine how much sooner you would hear the train, we need to calculate the difference in time it takes for the sound to travel through these two mediums.

When the train is 100 km away, we get the following:

  1. Time through air: 100000 m / 331.5 m/s = 301.66 seconds
  2. Time through iron: 100000 m / 5130 m/s = 19.49 seconds

The difference is, therefore, approximately: 301.66 - 19.49 = 282.17 seconds. Thus, the sound will reach you 282 seconds sooner if you listen to the rails rather than the air.

Learn more about Speed of Sound here:

brainly.com/question/35989321

#SPJ12


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Answers

Answer:

The sentence that describes the movement of matter and energy in the water cycle is:

C. Energy from sunlight warms the ocean surface and causes water to evaporate.

Explanation:

In the water cycle, energy from sunlight plays a crucial role in causing water to evaporate from the ocean surface. This evaporation process occurs when the sun's energy heats up the water, increasing its temperature. As a result, the water molecules gain enough energy to break free from the liquid state and transform into water vapor, which rises into the atmosphere. This step represents the movement of both matter (water) and energy (sunlight) in the water cycle.

If this answer is not correct I am truly sorry.

The grid in a triode is kept negatively charged to prevent...-the variations in voltage from getting too large
-the electrons from being attracted to the grid instead of the anode
-electrons from escaping from the tube containing the triode

Answers

I think the correct answer is the third statement, electron from escaping from the tube containing the triode. The negative charge on the grid repels any electron in the tube. As a result,the flow of current is controlled. If the field is that strong, all current flow will stop resulting to maintaining the electron cloud in the tube. 

Answer:

B. the electrons from being attracted to the grid instead of the anode.

Explanation:

just because its the answer

A thin conducting plate 50.0 cm on a side lies in the xy plane. If a total charge of 4.00 ? 10 ?8 C is placed on the plate, find (a) the charge density on the plate, (b) the electric field just above the plate, and (c) the electric field just below the plate.

Answers

Answer:

a) 8*10^-8C/m²

b) +9.04*10^3N/C

c) = -9.04*10^3N/C

Explanation:

Given

Side length, L = 50cm = 0.5m

Charge on the plate, Q = 4*10^-8C

Surface charge density, σ = Q/A

The surface charge density of each part is then half of the total charge density of the plate. Thus,

σ(face) = 1/2σ

σ(face) = Q/2A

σ(face) = Q/2L²

Now we plug in, since we have Q and L

σ(face) = 4*10^-8 / 2*0.5²

σ(face) = 4*10^-8 / 0.5

σ(face) = 8*10^-8C/m²

Magnitude of electric field above the plate is,

E = σ(face) / E•

E = 8*10^-8 / 8.85*10^-12

E = 9.04*10^3 N/C

If we assume this plate lies on the side of the "xy" plane, the electric field is directed in the positive "z" direction. As such,

E = +9.04*10^3N/C

Electric field below the plate has the same magnitude, but different direction. So, E = -9.04*10^3N/C

If you know the distance an object has traveled in a certain amount of time you can determine

Answers

With that information, you can determine the object's speed.
Just divide the distance covered by the time to cover the distance.

If you also know the direction the object moved, then you can
determine its velocity.  If you don't, then you can't.
You can determine the velocity it is moving at. 

Plizz help meeee thanks and have a wonderful day ​

Answers

Answer:

This is a Upside down Glass of Water Experiment

Explanation:

Explanation:

if I interpret the graphic correctly, then there is a basin fully filled with water on the left, then a piece of paper of a piece of glass, where the paper is in contract with the water on the left, and some water is delivered to the right.

then i suspect this shows the capillary effect of very narrow channels of water. like in the very tiny spaces between the fibers of the paper. as long as the paper is in contact with the water on the left, and the level of water is there higher than on the right, the surface tension of water kind of propels itself further along these narrow channels in the paper and supported by gravity and air pressure it drops even into the other side.

The relationship between a cathode and an anode involvesA. protons.
B. diodes.
C. electrons.
D. neutrons.

Answers

Cathode andanode always go together in electrochemical reactions. An example of this isthe lead battery. The lead battery contains a chemical that is involved in thechemical reaction. The chemical reaction in the battery causes a buildup ofelectrons in the anode. And because the electron buildup in the anode is full,its only place to go is the cathode. The movement of the electrons from anodeto cathode is caused by the chemical reaction present in the battery. There willbe a movement until the chemical runs out. If the chemical runs out, theelectrons stop moving. The answer is c.

THE ANSWER IS *ELECTRONS* I toojk the pen foster exam! <3 hope this helps