Please help me this is the last problem i have left. I am struggling with b and c An electron with a total energy of 19GeV travels through an accelerator tube with proper length 7.7km.

a) What is the length of the tube in the electron's frame? Le=

m

b) How long does it take in the frame of the electron? te=

s

c) How long does it take in the frame of the tube? tt=

s

Note: the rest energy of an electron is: E0=0.51MeV.