1. Simple Harmonic Motion

2. Periodic Motion When a vibration or oscillation repeats itself over the same time period

3. Oscillating Spring System Equilibrium position- where spring exerts no force on the mass (m) Natural state

4. Oscillating Spring System Spring stretched Exerts a force to move it back to equilibrium

5. Oscillating Spring System Spring compressed Force exerted pushing it back to equilibrium

6. Restoring Force (F) Force exerted when away from equilibrium Directly proportional to the displacement (x) F = - kx k – spring constant Greater the value of k the more force is needed to stretch spring - stiffer

7. F is not constant, depends on x F = ma Therefore acceleration is not constant, depends on x

8. Question At what position(s) is the acceleration the greatest? Where is it the least? Where is velocity greatest? And least?

9. Other Definitions Amplitude (A) – point of greatest displacement Cycle – complete oscillation Period (T) – time for one complete oscillation Frequency (f) – cycles per second T = 1/f

10. Example When a family of four people (total mass 200kg) steps into their 1200kg car, the springs compress 3.0 cm. A) What is the car’s spring constant? B) How far will the car lower if loaded with 100kg of luggage as well?

11. Example A.10 kg object is suspended from a spring with a spring constant of 10 N/m. The object is pulled 15cm from its equilibrium position and released, what is its maximum acceleration and when does it experience this?

12. Simple Harmonic Motion (SHM) Any vibrating system where the restoring force is directly proportional to the negative displacement Any object exhibiting this is called a simple harmonic oscillator (SHO)