What you’ll learn15 learning objectivesChoose one objective for a focused lesson, or study the complete topic.—A.5.1 (HL)—Reference frames• Reference frames.Syllabus objective—A.5.2 (HL)—Galilean relativity• Galilean relativity: Newton’s laws are identical in all inertial frames.Syllabus objective—A.5.3 (HL)—Galilean transformations• Galilean transformations: x′=x-vt and t′=t.Syllabus objective—A.5.4 (HL)—Galilean velocity addition• Galilean velocity addition: u′=u-v.Syllabus objective—A.5.5 (HL)—Two postulates of special relativity• Two postulates of special relativity.Syllabus objective—A.5.6 (HL)—Lorentz transformations• Lorentz transformations relate event coordinates between inertial frames.• Use γ and the two inertial-frame coordinates x, t and x′, t′.Syllabus objective—A.5.7 (HL)—Relativistic velocity addition• Relativistic velocity addition: u′=(u-v)/(1-uv/c^2).Syllabus objective—A.5.8 (HL)—Space-time interval• Space-time interval is invariant: (Δs)^2=(cΔt)^2-(Δx)^2.Syllabus objective—A.5.9 (HL)—Proper time interval and proper length• Proper time interval and proper length.Syllabus objective—A.5.10 (HL)—Time dilation• Time dilation: Δt = γΔt0.Syllabus objective—A.5.11 (HL)—Length contraction• Length contraction: L = L0/γ.Syllabus objective—A.5.12 (HL)—Relativity of simultaneity• Relativity of simultaneity.Syllabus objective—A.5.13 (HL)—Space-time diagrams• Space-time diagrams.Syllabus objective—A.5.14 (HL)—World lines and speed• On space-time diagrams, world-line angle relates to speed: tan θ = v/c.Syllabus objective—A.5.15 (HL)—Muon decay evidence• Muon decay is experimental evidence for time dilation and length contraction.Syllabus objective