Final answer:
Classical mechanics is a well-tested model that can be derived from special relativity in everyday situations where speeds are small compared to the speed of light. Time dilation and length contraction are two surprising outcomes of special relativity that are not observed in everyday life. The deviation from classical physics predicted by relativity can be calculated for specific speeds and can result in small cumulative time differences.
Step-by-step explanation:
Classical mechanics is a well-tested model that has been verified by hundreds of years worth of experiments and engineering feats. However, special relativity can still be derived from classical mechanics in situations where speeds are small compared to the speed of light. Two surprising outcomes of special relativity are time dilation and length contraction, which show that measured intervals in time and space are not absolute quantities and can appear differently to different observers.
The equations for time dilation and length contraction are t = t0/sqrt(1 - (u^2/c^2)) and l = l0/sqrt(1 - (u^2/c^2)), respectively, where u is the speed of the object and c is the speed of light. When u is much smaller than c, these equations reduce to the equations of classical physics, meaning that time dilation and length contraction are not observed in everyday life.
In the case of a spy plane moving at 1500m/s, which is fast compared to everyday situations, the deviation from classical physics predicted by relativity (??1) can be calculated using the binomial expansion and the first two terms. The result is approximately 1.250×10^-11, meaning there would be a small cumulative time difference of about 28ms after living for 70 years in such a spy plane compared to people at rest relative to the Earth.
Finally, the relativistic velocity addition formula states that the sum of two speeds in relativity is given by speed = (v + u)/(1 + (vu/c^2)). In the case of v = u = 0.01c, the relativistic sum of the two speeds is approximately 0.02010c, or 2.010% of the speed of light.