1. Forces - basic physics Gravity Friction - static and kinetic Viscosity
Springs (Hooke’s law)
Damping

2. Friction Supporting object Fs Resting contact F FN Normal force
Static friction Fs
Resting contact F
Normal force FN

3. Friction Supporting object Kinetic friction Fk v Resting contact F FN
Normal force
Static friction

4. Gravity

5. Viscosity kv - depends on shape of object
n - depends on properties of liquid
For spherical object:
Terminal velocity - viscosity and gravity balance
E.g., for sphere:

6. Springs (Hooke’s law) Spring’s rest length: exerts zero force x xrest

7. Spring Mesh
Edges => springs
Internal springs to stabilize shape

8. Damping
Calm down spring oscillations

9. Forces - Recap Based on position: springs, gravity, wind,
Based on velocity: viscosity, dampers,
Based on other forces: static and kinetic friction
Give rise to accelerations
Based on object interactions: collisions, friction