Matter within the international space station experiences apparent weightlessness. If an astronaut needs to determine the mass of a substance, they can not use a traditional electronic balance or scale based on gravitational weight, like we do on Earth. Instead they use a Mass Measurement Device or an Inertial balance which is essentially a mass-spring simple harmonic oscillator. Consider an inertial balance with a spring constant k = 655 N/m. A large sample of dehydrated plant root is placed in the balance and is set into simple harmonic motion. If the frequency of motion is measured to be f = 3.55 Hz, then determine the following:

A. The period of oscillation, T.
B. The mass of the dehydrated plant root sample.
The same sample is again set into motion, but this time with half the original amplitude of oscillation. Determine the new period of oscillation and the mass of the sample without making a new calculation. Briefly explain your reasoning.

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.