IB Physics HL A.5.7 Relativistic velocity addition Question Bank

Practise IB Physics HL A.5.7 by applying relativistic velocity addition concepts to exam-style physics questions.

Exam points

identify the relevant physical quantity, model or diagram
apply the correct equation and units to the evidence
justify the result using conservation laws, forces or energy relationships

[Maximum number: 2]

An observer P sitting in a train moving at a speed v measures that his journey takes a time $\Delta t_{\mathrm{p}}$ . An observer Q at rest with respect to the ground measures that the journey takes a time $\Delta t_{\mathrm{Q}}$ .

A second train is moving at a velocity of -0.70 c with respect to the ground.

Figure for Question A.5.7 (HL)—Relativistic velocity addition question 1 — IB Physics HL

Calculate the speed of the second train relative to observer P .

$\begin{aligned} u^{\prime}=\frac{-0.7-0.6}{1+0.7 \times 0.6} \text { c } =\ll->0.92 \mathrm{c} \end{aligned}$

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A.5.7 (HL)—Relativistic velocity addition question 1