In the laboratory, a spectral line of an element has a wavelength of 5000 Angstroms. What would be the measured wavelength of that line in the spectrum of a planet which is approaching at a velocity of 30 km/s? (The speed of light is 300,000 km/s.)

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?