Mildly educational, and it’s free
Needs a little more development work, methinks.

Explore physics concepts with a spring pendulum simulation. Manipulate parameters like damping, spring flexibility, and mass to observe oscillations. Record and export displacement graphs for deeper analysis.
1.2
June 10, 2017
This app has been updated by Apple to display the Apple Watch app icon. - support for iOS 9.1
MoreDR.Osci.HD is a free physics simulation app that allows you to explore the behavior of a spring pendulum. You can interact with the simulation by touching the mass or tilting your device, and adjust parameters like damping, spring flexibility, and mass.
The app is designed for educational purposes, focusing on harmonic and non-harmonic oscillations. It helps users understand how different parameters affect the motion of a spring pendulum.
Yes, you can record the displacement of the mass over time by tapping the graph button. These graphs can then be exported to your photo library for further study.
No, DR.Osci.HD is ad-free, providing an uninterrupted learning experience.
DR.Osci.HD is available for iPhone, iPad, and iPod devices and is rated for ages 4 and up.
The app was last updated on June 10, 2017, to version 1.2. It was originally released on June 17, 2015.
The app states that the simulation is an approximation and might differ from reality. It is intended for educational purposes and should be used at your own risk.