327,360 feet
most aviation experts agree that the point where space begins is approximately 62 miles up. (62x5280=327,360).
According to Doppler Effect, an observer at rest will perceive a shift in the wavelength or frequency of the radiation emitted by a source in movement.This shift is given by the formula:

where:

= observed wavelength

= wavelength at rest
v = speed of source (positive if towards the observer, negative if away from the observer)
c = speed of light
Therefore, we can solve for the observed wavelength:

Substituting the given data:

= 655.80 nm
Hence, the observed wavelength of the line would be
655.80 nm. Note that this value is smaller than the one at rest, which means that we have a blue-shift, as expected for an approaching source.
Answer: it becomes a positive ion
Explanation:
So, when an atom loses 2 electrons there will be no change in the number of neutrons. Therefore, an isotope will not form. Thus, it is concluded that when an atom with no charge loses two electrons, it becomes a positive ion.
Answer:
Speed, v = 312.34 m/s
Explanation:
The equation that describes a transverse wave on the string is given by :
..............(1)
Where
y = displacement of a string particle
x = position of the particle on the string
The wave is travelling in the +x direction. We have to find the speed of the wave.
The general equation of traverse wave is given by :
................(2)
On comparing equation (1) and (2) we get,
k = 3 rad/m
Since, 
..............(3)
Also, 
Since, 
...............(4)
Speed of the wave is the product of frequency and wavelength i.e.

Using equation (3) and (4), the speed of the wave can be calculated as :

v = 312.34 m/s
Hence, the speed of the transverse wave is 312.34 m/s
You multiply your average speed with the time for which you have been traveling