According to Einstein‘s theory of special relativity, an object's mass changes as it moves faster and faster, and eventually the mass becomes infinite as the object approaches the speed of light. This relative mass of an object based on its velocity can be found by.
m = [tex]\frac{m}{\sqrt{1-\frac{v^{2} }{c^{2} } } }[/tex]
(relative)
Using this formula to determine the relative mass of Santa while he’s in flight if he is normal mass, M,is typically 175 kg