DP Physics (last assessment 2024)
Question 19M.3.SL.TZ2.7cii
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.SL.TZ2.7cii |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | Determine | Question number | cii | Adapted from | N/A |
cii.
[Maximum mark: 1]
19M.3.SL.TZ2.7cii
A spaceship moves away from the Earth in the direction of a nearby planet. An observer on the Earth determines the planet is 4 ly from the Earth. The spacetime diagram for the Earth’s reference frame shows the worldline of the spaceship. Assume the clock on the Earth, the clock on the planet, and the clock on the spaceship were all synchronized when ct = 0.
(cii)
Determine, according to an observer on the spaceship as the spaceship passes the planet, the time shown by the clock on the planet.
[1]
Markscheme
t = 5 years OR ct = 5 ly ✔
Examiners report
Many candidates tried to use time dilation again without realising that the clock on P must also read 5 years at event E because that is the time on the Earth clock in P’s frame for the event.
