To determine the energy equivalent of an object, we use the famous equation of Einstein which is E=mc^2 where m is the mass of the object and c is the speed of light (3x10^8 m/s). We calculate as follows:
E = mc^2
E = 4.1 kg (3x10^8 m/s)^2
E = 3.69x10^17 J
It would be 5 mph. Hope it helps! :)
Separation of light into different color is called "dispersion". Rainbow, comes from refraction and reflection of sunlight, in the falling raindrops, which means that that the refractive index of water depends on the wavelength of light.