Simple Pendulum Restoring Torque — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Simple Pendulum Restoring Torque Applies to the rotational motion of a simple pendulum, describing the torque that pulls it back towards the equilibrium position. Consider the gravitational force (mg) acting vertically downwards on the bob. Resolve mg into components: one radial (along L) and one tangential (perpendicular to L). The tangential component ( F t ) is the restoring force: F t = -mg . Torque ( ) is calculated as the perpendicular distance (L) multiplied by the force: = L F t . Resulting torque: = -m g L . must be measured in radians. L > 0 m > 0 Forgetting the negative sign, which indicates that the torque always opposes the displacement (restoring nature). Using the small angle approximation ( ) when the angle is large. Confusing the restoring force (tangential) with the net force (which includes the radial component).