DP Physics (last assessment 2024)
Question 19N.3.SL.TZ0.b
| Date | November 2019 | Marks available | [Maximum mark: 1] | Reference code | 19N.3.SL.TZ0.b |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Outline | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
19N.3.SL.TZ0.b
A train is moving across a bridge with a speed v = 0.40c. Observer A is at rest in the train. Observer B is at rest with respect to the bridge.
The length of the bridge LB according to observer B is 2.0 km.
Outline why LB is the proper length of the bridge.
[1]
Markscheme
LB is the length/measurement «by observer B» made in the reference frame in which the bridge is at rest ✔
NOTE: Idea of rest frame or frame in which bridge is not moving is required.
