When pulled sideways and released, weight {pendulum} hanging by string or wire from point starts oscillating motion.
force
Pendulum restoring force is gravity. Gravity g pulls pendulum-bob mass m back toward center with force F from distance x, depending on displacement angle A: F = m * g * sin(A) = m * k * x.
distance
If pendulum displacement is small, displacement-angle sine equals displacement angle: sin(A) = A. For small displacement, displacement x is displacement angle, expressed in radians, times pendulum length L: x = A*L. For small displacement, constant k is gravity acceleration g divided by pendulum length L: k = g/L.
period
Pendulum period T is 360 degrees, expressed in radians 2*pi, times square root of gravitational-constant reciprocal 1/g: T = 2 * pi * (1/g)^0.5. Longer pendulums have longer periods. Weaker gravity makes longer period. Pendulum mass does not affect period.
Physical Sciences>Physics>Dynamics>Force>Kinds>Restoring
5-Physics-Dynamics-Force-Kinds-Restoring
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Date Modified: 2022.0224