Circular motion requires a continuous inward (centripetal) force. In uniform circular motion (UCM), speed is constant but velocity changes direction, producing centripetal acceleration a_c = v^2/r = r*omega^2 toward the centre. The centripetal force F_c = mv^2/r is NOT a separate force — it is the net radial component of real forces (tension, gravity, friction, normal force).

Non-uniform circular motion adds a tangential component a_t = dv/dt, making a_net = sqrt(a_c^2 + a_t^2). The net force is NOT purely radial.

Vertical circle is the most tested topic. For a mass on a string: v_top_min = sqrt(gL), v_bottom_min = sqrt(5gL), and T_bottom - T_top = 6mg always. For a rigid rod: v_top = 0 is allowed, so v_bottom_min = 2*sqrt(gL).

Banked roads: Without friction, tan(theta) = v^2/(rg) gives one safe speed. With friction, a speed range [v_min, v_max] exists. A conical pendulum has period T = 2pisqrt(L*cos(theta)/g).

Key approach: identify real forces, resolve into radial and tangential, set net radial force = mv^2/r. Never add centrifugal force in the inertial frame.