Dynamics · Physics

Circular Motion (Dynamics)

Circular motion needs inward acceleration — and that means a net inward force.

This topic includes

Subtopics to master

Focus on centripetal acceleration and the source of the centripetal force in real systems.

Kinematics
Centripetal Acceleration
The acceleration points toward the center: ac = v²/r for constant speed circles.
  • Direction is inward
  • Magnitude relation v²/r
  • Constant speed vs changing speed
Start subtopicDon’t confuse with velocity.
Dynamics
Centripetal Force Requirement
Net inward force must satisfy ΣFrad = m v²/r.
  • Not a new kind of force
  • It’s the net radial force
  • Radial vs tangential
Start subtopicNet force view.
Sources
Sources of Centripetal Force
Identify what provides the inward force: tension, friction, normal force components, gravity, etc.
  • Tension in a string
  • Friction on a curve
  • Normal force on a banked turn
Start subtopicFind the provider.
Case
Circular Motion at Constant Speed
Use radial equations with constant speed to solve for unknowns (v, r, force).
  • Radial FBD logic
  • Component choice
  • Common sign mistakes
Start subtopicStandard problem type.
Intro
Banking and Vertical Circular Motion
Intro to banked curves and vertical circles: forces change with position and orientation.
  • Bank angle intuition
  • Top/bottom of vertical circle
  • Minimum speed idea (intro)
Start subtopicPreview of harder sets.
Practice
Practice & Exercises
Radial-force problems: identify the centripetal provider and solve ΣFrad=mv²/r.
  • Compute ac from v and r
  • Find required force for a turn
  • Friction-provided centripetal sets
  • Tension + circular motion drills
  • Intro banked/vertical circle practice
Open practiceRadial thinking becomes natural.