[填空题]
(a) What is the spee qztud cxxa pq3fm7);i7vq*52d8ka(+fp(j zd0vcfp f iv 2x)c.*. weob $v$ of an electron whose kinetic energy is 14,000 times its rest energy? You can state the difference $c - v$. Such speeds are reached in the Stanford Linear Accelerator, SLAC. m/s less than c
(b) If the electrons travel in the lab through a tube 3.0 km long (as at SLAC), how long is this tube in the electrons' reference frame? [Hint: use the binomial expansion.]L = cm
