A sound wave traveling at 343 m/s is emitted by the foghorn of a tugboat. an echo is heard 2.80 s later. how far away is the ref
1 answer:
The echo is heard 2.80 s later, this means this is the time the sound takes to travel to the reflecting object and then back to us. So, during this time, the sound wave has covered the distance L between us and the object twice:
The speed of the sound wave is:
, and since it is moving by uniform motion, we can find the distance covered by the wave using
And we said this corresponds to twice the distance between us and the reflecting object, so:
so, the object is 480 meters away.
The speed of the sound wave is:
And we said this corresponds to twice the distance between us and the reflecting object, so:
so, the object is 480 meters away.
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Answer:
A gravitational force of 6841.905 newtons is exerted on the satellite by the Earth.
Explanation:
At first we assume that Earth is represented by an uniform sphere, such that the man-made satellite rotates in a circular orbit around the planet. Hence, the following condition must be satisfied:
(1)
Where:
- Period of rotation of the satellite, measured in seconds.
- Distance of the satellite with respect to the center of the planet, measured in meters.
- Gravitational constant, measured in newton-square meters per square kilogram.
- Mass of the Earth, measured in kilograms.
Now we clear the distance of the satellite with respect to the center of the planet:
(2)
If we know that ,
and
, then the distance of the satellite is:
The gravitational force exerted on the satellite by the Earth is determined by the Newton's Law of Gravitation:
(3)
Where:
- Mass of the satellite, measured in kilograms.
- Force exerted on the satellite by the Earth, measured in newtons.
If we know that ,
,
and
, then the gravitational force is:
A gravitational force of 6841.905 newtons is exerted on the satellite by the Earth.