A student attempted to obtain the equation of motion of a simple pendulum and wrote the following sequence:
mdt2d2s=−mgθ,s=Lθ⇒dt2d2s+Lg=0.
(i) Locate the incorrect step in the above working and explain the error logically.
(ii) Rewrite the correct form of the differential equation of motion.
(iii) Using the corrected equation, explain how one recognises that the motion of the bob is simple harmonic and identify the angular frequency ω.