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o-na [289]
3 years ago
7

In old times, before there were train signals, people who worked on the railroad would often put their ear down to the train tra

ck to listen for an oncoming train. Why would this result in hearing the train further off than just listening for the train through the air? Question 3 options: Sound travels slower in air because there are often trees and other items blocking the sound. People did not do this because sound travels faster through less dense material, like air, rather than more dense materiel, like train tracks. Sound travels slower, but louder through solid material because it is more dense, so the train could be heard better this way. Sound waves travel faster in more dense material, and the more dense the material the faster the sound is.
Physics
1 answer:
elena55 [62]3 years ago
8 0
The answer is the second option or B.
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kati45 [8]

Answer:

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Explanation:

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3 years ago
A motor has a rotor (with armature) of moment of inertia ????m . The rotor is attached to a gear box of gear ratio G > 1. The
Inessa [10]

Answer:

hello your question is incomplete attached below is the complete question

answer : The moment of inertial felt by someone ( J ) is greater that the moment of inertia felt by the motor  i.e. J > Jm

Explanation:

Gear ratio G > 1

a) Determine the moment of inertia felt by the motor

moment of inertia felt by Motor = moment of Inertia at the armature

b) Determine the moment of inertial felt by someone who is rotating the mass by hand

moment of inertia felt by someone is = J

The moment of inertial felt by someone ( J ) is greater that the moment of inertia felt by the motor

attached below is a detailed solution

3 0
3 years ago
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Mrrafil [7]

Answer:

A) T.

Explanation:

Kepler's third law states that the orbital period (T) of a satellite is related with the radius (R) and the mass of the object (M) it orbits:

T=\frac{2\pi R^{\frac{3}{2}}}{\sqrt{GM}}  

So the orbital period is independent of the mass of the satellite, that means no matter the mass every satellite at a radius R around the earth have an orbital period A.

4 0
3 years ago
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Tom [10]

Answer:

4th answer

Explanation:

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gradient = distance / time = speed

Here, the gradient is a constant till 30s. So it has travelled at a constant speed. It means it had not accelarated till 30s. and has stopped moving at 30s.

6 0
2 years ago
Which of the following is a non renewable resource?
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