Question 1
A supertrain (rest-length = 100 m) travels at a speed of 0.950 c as it passes through a tunnel (rest-length 50.0 m). As seen by a trackside observer, is the train ever completely within the tunnel? If so, by how much?
Question 2
Find the momentum and speed of a proton whose kinetic energy equals its rest energy. (The mass of a proton is 938.3 MeV/c2).