DP Physics (last assessment 2024)

Question 17N.3.HL.TZ0.12

Date	November 2017	Marks available	[Maximum mark: 4]	Reference code	17N.3.HL.TZ0.12
Level	HL	Paper	3	Time zone	TZ0
Command term	Explain, Outline	Question number	12	Adapted from	N/A

12.

[Maximum mark: 4]

17N.3.HL.TZ0.12

A farmer is driving a vehicle across an uneven field in which there are undulations every 3.0 m.

The farmer’s seat is mounted on a spring. The system, consisting of the mass of the farmer and the spring, has a natural frequency of vibration of 1.9 Hz.

(a)

Explain why it would be uncomfortable for the farmer to drive the vehicle at a speed of 5.6 m s^–1.

[3]

Markscheme

ALTERNATIVE 1

the time between undulations is $\frac{3}{{5.6}}$ = 0.536 «s»

f = $\frac{1}{{0.536}}$ = 1.87 «Hz»

«frequencies match» resonance occurs so amplitude of vibration becomes greater

Must see mention of “resonance” for MP3

ALTERNATIVE 2

f = $\frac{v}{\lambda } = \frac{{5.6}}{3}$

f = 1.87 «Hz»