If an airplane flies at 450 m/s around the planet, and the earth's circumference is about 4.01 x 107 m, calculate the time dilation for an around-the-world trip. ignore the earth's rotation and gravity 4.) in the rest frame of the sample, the number of muons at time t is given by n(t) = noe t/7, where no is the number at 0, and t is the mean lifetime (or "half life") of 2.2 us. a) assume the muons are produced at a height of 6.0 km, and head toward the ground as a speed of 0.91c. what fraction will reach the ground? b) what fraction would reach the ground if classical mechanics were correct?