Use battery–operated vehicle moving at constant speed. Place vehicle on butcher paper ∼1.5 m long so tractor moves transverse to longer dimension of paper. First, run tractor with paper stationary. Repeat, while pulling paper by hand at as constant speed as possible. Repeat with tractor moving in direction of paper motion and opposite to paper motion. Try moving paper at same speed as tractor but in opposite direction so tractor remains motionless in lab frame.
DISCUSS classic problem of rowing to point directly across a swiftly moving river. If appropriate, explain why a light source, moving at speed of light, does not result in “stopping” light beam.