Motion in a circle — CIE A-Level Physics
1. Unit at a glance
This unit builds on your existing knowledge of linear motion to describe motion along a circular path. We start by defining new rotational quantities that simplify describing circular motion, before moving to the key insight that uniform circular motion requires constant acceleration directed towards the center of the circle.
Topics build sequentially: you will first learn how to describe how fast an object rotates, then calculate its acceleration, then find the net force required to keep it moving in a circular path. This sequence mirrors how you learned linear motion earlier in your course.
Common Pitfalls
Why: This leads to incorrect free-body diagrams and wrong calculations for net force.
Why: This fictitious force only appears in non-inertial reference frames and is not required for CIE A-Level problems.