Time taken for a message to sent from earth to reach the first astronauts is 140 second.
It takes about three days for a spacecraft to reach the Moon. in the course of that time a spacecraft travels at the least 240,000 miles 386,400 km that is the space between Earth and the Moon. The specific distance depends at the specific path selected.
The distance from earth to moon is approximately3.84*108m
So, the distance from earth to the astronauts is3.84*108m - 10500*103m =3.735*108m
The speed of light c = 2.99792458*108m/s
So, divided the distance from earth to astronauts by the speed off light,
3.735*108m/2.99792458*108m/s ˜1.25seconds
Divided the Pluto-earth distance by speed of light:
Hence, 4.2*1010m/2.99792458*108m/s = 140seconds
Learn more about astronauts here:-brainly.com/question/24496270
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B. The number of field lines on the source charge.
Ek = 1/2 mv^2
9 × 10^4 = 1/2 × 800 × v^2
9 × 10^4/400 = 400 v^2 / 400
9 × 10^4/400 = v^2
√225 = v
15 ms⁻¹ = v
That's the only way I know how to work it out
I think in this case velocity and speed would be considered the same because me
s = d/t and v=d/t
one is distance travelled and the other is displacement of a body
The first resonant position below the open end of the resonance tube is; <em><u>one-quarter of the wavelength</u></em>
In the event of the first resonant position in a resonance tube, there will be a maximum air displacement which is only one antinode right at the open end where the motion is constrained.
However, there will be no displacement at the closed end which means another one node right at the closed end where air is halted.
This means that the standing wave will have one-quarter of the wavelength in the test tube.
Thus;
L = ¼λ
Read more at; brainly.com/question/17086525
They eat rice, chicken, beef, cereal they eat what we eat in a daily basis I guess