Question 23M.3.SL.TZ2.5
| Date | May 2023 | Marks available | [Maximum mark: 5] | Reference code | 23M.3.SL.TZ2.5 |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Determine, Estimate | Question number | 5 | Adapted from | N/A |
The spacetime diagram shows the Earth frame with the worldline of a spaceship S moving away from Earth. ct′ = 0 when ct = 0.
Determine the speed of the spaceship relative to Earth.
[1]
0.6 c
OR
= 1.8 × 108 «m s−1» ✓
A flash of light sent by an Earth observer at ct = 2.0 km is directed towards the spaceship.
Estimate, using the spacetime diagram, the time in seconds when the flash of light reaches the spaceship according to the Earth observer.
[2]
Line drawn at 45° from ct = 2 km to hit spaceship world line at ct = 5 km
OR
ct = 1.2/(c − 0.6c) + 2 = 5 «km» ✓
t = = 1.7 × 10−5 «s» ✓
Award [2] for BCA
Determine the time coordinate ct′ when the flash of light reaches the spaceship, according to an observer at rest in the spaceship.
[2]
(ct')2 − 0 = 52 − 32
OR
= 1.25 ✓
ct' = 4 «km»
OR
t' = 13 «µs» ✓
Allow ECF from (b)
Allow ECF from MP1