In this example we will see that time dilation is a rather smalleffect for reference frames in which u≪c. An airplane flies fromSan Francisco to New York (about 4800 km, or 4.80×106m) at a steadyspeed of 300 m/s (about 670 mi/h) (Figure 1). How much time doesthe trip take, as measured (a) by observers on the ground and (b)by an observer inside the plane?The π+ meson (or positive pion) isan unstable particle that has a lifetime (measured in its restframe) of about 2.60×10−8s. If the particle is moving with a speedof 0.992 c with respect to your laboratory, what is its lifetime asmeasured in the laboratory?
