A 1 kg ball suspended from a point on a smooth horizontal bar of mass 4 kg is released from 30° with the vertical. Find the bar displacement when the string reaches maximum angle on the other side.

Question

G1 Physics · Accepted Answer

With zero external horizontal force, the centre of mass has constant velocity and ΣmᵢΔxᵢ = 0 in the centre-of-mass relation. Applying this to the given motion gives B: 0.2 m.