Question 18M.3.SL.TZ1.a
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.3.SL.TZ1.a |
| Level | SL | Paper | 3 | Time zone | TZ1 |
| Command term | Draw | Question number | a | Adapted from | N/A |
An observer on Earth watches rocket A travel away from Earth at a speed of 0.80c. The spacetime diagram shows the worldline of rocket A in the frame of reference of the Earth observer who is at rest at x = 0.
Another rocket, B, departs from the same location as A but later than A at ct = 1.2 km according to the Earth observer. Rocket B travels at a constant speed of 0.60c in the opposite direction to A according to the Earth observer.
Draw on the spacetime diagram the worldline of B according to the Earth observer and label it B.
[2]
straight line with negative gradient with vertical intercept at ct = 1.2 «km»
through (–0.6, 2.2) ie gradient = –1.67
Tolerance: Allow gradient from interval –2.0 to –1.4, (at ct = 2.2, x from interval 0.5 to 0.7).
If line has positive gradient from interval 1.4 to 2.0 and intercepts at ct = 1.2 km then allow [1 max].
[2 marks]