### Mechanics

Schematic of system

1. Adjust knob, 2. Arm, 3. Hook, 4. Spring, 5. Initial weights, 6. Pointer, 7. Hook, 8. Mirror, 9. Weight tray, 10. Vernier, 11. Ruler, 12. Leveling screw, 13. Weights 14. Magnet, 15. Integrated Hall switch sensor, 16. Wiring socket, 17. Counter display, 18. Timer display, 19. Reset button, 20. Set/View button, 21. Trigger indicator LED.

## LEMI-21 Simple Harmonic Motion and Spring Constant

Features

• High accuracy timing device

• Affordable

Introduction

This experimental apparatus integrates two innovative devices into a Jolly balance: a reading device using a pointer and a reflective mirror with a vernier; and a timing device using an integrated Hall switch sensor. Its performance has been greatly improved from conventional apparatus. Through these experiments, students can understand the law of a spring oscillator for simple harmonic motion, and learn how to measure vibrational period. It can be used for general physics teaching.

Using this apparatus, the following experiments can be conducted:

1. Verify Hooke's law, and measure the stiffness coefficient of a spring

2. Study the simple harmonic motion of a spring, measure the period, calculate the stiffness coefficient of the spring

3. Study the properties and use method of a Hall switch

Parts and Specifications

 Description Specifications Jolly balance ruler Range: 0 ~ 551 mm; reading accuracy: 0.02 mm Counter/ timer Accuracy: 1 ms, with storage function Spring Wire diameter: 0.5 mm; outer diameter: 12 mm Integrated Hall switch sensor Critical distance: 9 mm Small magnetic steel Diameter: 12 mm; thickness: 2 mm Weight 1 g (10 pcs), 20 g (1 pc), 50 g (1 pc)

Schematic of system

1. Adjust knob, 2. Arm, 3. Hook, 4. Spring, 5. Initial weights, 6. Pointer, 7. Hook, 8. Mirror, 9. Weight tray, 10. Vernier, 11. Ruler, 12. Leveling screw, 13. Weights 14. Magnet, 15. Integrated Hall switch sensor, 16. Wiring socket, 17. Counter display, 18. Timer display, 19. Reset button, 20. Set/View button, 21. Trigger indicator LED.