Physics Lens

04. Forces

Types of Forces

  • Static friction
    • Frictional force between surfaces at rest with respect to each other.
    • It increases with increasing applied force up to a maximum value (which is proportional to normal contact force).
  • Kinetic friction
    • Frictional force acting between surfaces in relative motion.
  • Viscous forces
    • Resistive force experienced by a solid moving in a fluid.
    • Dependent on speed of object v, e.g. $$F_D\propto v$$ at low speeds and $$F_D\propto v^2$$ at high speeds.