IB Physics HL A 5 11 Hl Length Contraction Questions
Practise IB Physics HL A.5.11 by identifying proper length, calculating contraction parallel to motion and comparing the measurements of inertial observers.
Syllabus
First assessment 2025
Course
Physics HL
Level
HL
Exam points
Apply length contraction L = L₀/γ along the direction of motion.
Calculate proper length, observed length, speed or Lorentz factor using complete mark-scheme evidence.
An observer P sitting in a train moving at a speed v measures that his journey takes a time Δtp. An observer Q at rest with respect to the ground measures that the journey takes a time ΔtQ.
Later the train is travelling at a speed of 0.60 c . Observer P measures the length of the train to be 125 m . The train enters a tunnel of length 100 m according to observer Q .
Show that the length of the train according to observer Q is 100 m .