DP Physics (last assessment 2024)

Question 20N.3.SL.TZ0.4c

Date	November 2020	Marks available	[Maximum mark: 2]	Reference code	20N.3.SL.TZ0.4c
Level	SL	Paper	3	Time zone	TZ0
Command term	Calculate	Question number	c	Adapted from	N/A

[Maximum mark: 2]

20N.3.SL.TZ0.4c

A spaceship is travelling at $0.80 c$ , away from Earth. It launches a probe away from Earth, at $0.50 c$ relative to the spaceship. An observer on the probe measures the length of the probe to be $8.0 m$ .

(c)

Calculate the speed of the probe in terms of $c$ , relative to Earth.

[2]

Markscheme

$u = \frac{0.5 c + 0.8 c}{1 + \frac{0.5 c \times 0.8 c}{c^{2}}}$ ✓

$u = 0.93 c$ ✓

Allow all negative signs for velocities

Award [2] marks for a bald correct answer

Examiners report

Very well answered.

Syllabus sections

Option A: Relativity

Option A: Relativity » Option A: Relativity (Core topics) » A.2 – Lorentz transformations

Option A: Relativity » Option A: Relativity (Core topics)

Question 20N.3.SL.TZ0.4c

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