| Date | May 2017 | Marks available | 1 | Reference code | 17M.1.HL.TZ1.28 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Question number | 28 | Adapted from | N/A |
Question
A train moving at speed u relative to the ground, sounds a whistle of constant frequency f as it moves towards a vertical cliff face.
The sound from the whistle reaches the cliff face and is reflected back to the train. The speed of sound in stationary air is c.
What whistle frequency is observed on the train after the reflection?
A. \(\frac{{(c + u)}}{{(c - u)}}f\)
B. (c + u)f
C. (c – u)f
D. \(\frac{{(c - u)}}{{(c + u)}}f\)
Markscheme
A
Examiners report
[N/A]
