10) T F Two unequal weights are connected by a massless string which passes over a frictionless pulley. If the pulley has no app
2 answers:
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Answer:
0.80 c
Explanation:
The computation of speed is shown below:-
Here, The speed of the captain ship A report for speed of the ship B which is
where
indicates the speed of the ship A
indicates the speed of the ship B
and
C indicates the velocity of life
now we will Substitute 0.40c for A and 0.60 for B in the equation which is
after solving the above equation we will get
0.80 c
So, The correct answer is 0.80c
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.