A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from t
1 answer:
Answer:
The impact occured at a distance of 2478.585 meters from the person.
Explanation:
(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:
<em>A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)</em>
Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete (), in seconds:
(1)
Where:
- Time spent by the sound in concrete, in seconds.
- Time spent by the sound in the air, in seconds.
By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:
(2)
Where:
- Speed of the sound in concrete, in meters per second.
- Speed of the sound in the air, in meters per second.
- Distance traveled by the sound, in meters.
If we know that ,
and
, then the distance travelled by the sound is:
The impact occured at a distance of 2478.585 meters from the person.
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<h2>Answer:</h2><h2>The depth of barge float=3 cm</h2><h2>Explanation:</h2>
Length of rectangular barge=5.2 m
Width of rectangular barge=2.4m
Mass of crate=410 kg
Let h be the height of barge float
Volume of barge float=
Density of water=
Weight of water displaced by barge=Buoyant force=-Weight of horse
1 m=100 cm
cm
Hence, the depth of barge float=3 cm
<h2 />
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We don't see this in our daily life because it is not obvious that space and time are intertwined this way. This is a result of our lives spent at such slow speeds relative to the things around us.
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This is why we can talk about lightyears. It's not a unit of time, but distance light travels in a year. We are now free to define distance as a unit of time because we have a way to convert them.
As it turns out light is not special in that it gets to travel faster than anything else. Firstly, other things travel that fast too (gravity and information to name two). But NO events or information can travel faster than this. Not because they are not allowed to beat light to the finish line---remember my claim that light has nothing to do with it. It's because this speed (called "c") converts space and time. A speed greater than c isn't unobtainable---it simply does not exist. Period. Just like I can't travel 10 meters without actually moving 10 meters, I cannot travel 10 meters without also "traveling" at least about 33 nanoseconds (about the time it takes light to get 10 meters) There is simply no way to get there in less time, anymore than there is a way to walk 10 meters by only walking 5.
We don't see this in our daily life because it is not obvious that space and time are intertwined this way. This is a result of our lives spent at such slow speeds relative to the things around us.
This is the fundamental part to the Special Theory of Relativity (what you called the "FIRST" part of the theory) Here is where Einstein laid out the idea of spacetime and the idea that events (information) itself propagates at a fixed speed that, unlike light, does not slow down in any medium. The idea that what is happening "now" for you is not the same thing as what is "now" for distant observers or observers that are moving relative to you. It's also where he proposed of a conversion factor between space and time, which turned out to be the speed of light in vacuum.