This paper is about an experimental problem on forced oscillations, which was given to 14-year-old primary school pupils at the Slovenian national (final) level of the physics competition in April 2019. At the time when the competition took place these pupils were approaching the end of the school year, when they encountered physics as a school subject for the first time. The objectives of the experimental exam at the competition, the circumstances and the limitations are discussed. The final experimental setup, which is simple, inexpensive and purely mechanical is described and structured form of the problem is given and discussed. The results of the competition are briefly presented. As such, the experiment can also be used as content for an IBL lesson.