Introduction to Classical Mechanics · Problem 11.60

Relativity (Kinematics) — Morin

Physics — Mechanics · invariant-interval

Problem

Passing trains ** Train

A

with proper length

L

moves eastward at speed

v

, while train

B

with proper length

2L

moves westward also at speed

v

. How much time does it take for the trains to pass each other (defined as the time between the fronts coinciding and the backs coinciding): (a) In

A

's frame? (b) In

B

's frame? (c) In the ground frame? (d) Verify that the invariant interval is the same in all three frames.