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A: 2 concrete blocks 6cm apart will have the least gravitational attraction to each other.
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Answer:
B is the answers for the question
Answer:

Explanation:
d = Distance traveled = 40.8 km
s = Speed of jet = 340 m/s
Time is given by




The time taken to complete the journey is
.
Answer: Taking into account sound is a wave, we can use the information of the displacement (generally given as a graph) to find the wavelength and frequency, then we can calculate the speed with the formula of the speed of a wave.
Explanation:
If we have the displacement graph of the sound wave, we can find its amplitude, its wavelength and period (which is the inverse of frequency).
Now, if we additionally have the frequency as data, we can use the equation of the speed of a wave:

Where:
is the speed of the sound wave
is the wavelength
is the frequency