PHYSICS   LECTURE   DEMONSTRATIONS

M-S1   :   Diatomic Particle

UNIT: Center of Mass
PURPOSE: Illustrate the usefulness of the center of mass to describe oscillatory motion of two masses
EQUIPMENT:
1. PASCO 1m track
2. Two carts connected by a spring
3. CM marker, assorted weights
SUGGESTIONS: Demonstrate CM for: 
1. Uniform motion, no oscillations
2. Oscillating masses with CM stationary
3. Combined motions 1 & 2
4. Optional: oscillations with one mass held at rest (how does the frequency change?)
5. Optional: redo 3 varying the loads on carts
DISCUSSION:  Compressing the spring is a bit of a fine art; excessive compression will cause a deformation of the spring.

 

1.                 2.                 3.                 4.                 5.
    

1. Spring coupling of the two carts
2. The entire set-up, with the carts oscillating at the instant the spring is compressed
3. Close-up of the carts with the spring at its natural length
4. Extra 1kg on the left cart, spring compressed
5. Extra 1kg on the left cart, spring stretched