A particle moves in a vertical circle of radius R under gravity while constrained by a light string. At a point where the string makes angle θ with the vertically downward direction, which relations are correct?
Select all that apply

Question

A particle moves in a vertical circle of radius R under gravity while constrained by a light string. At a point where the string makes angle θ with the vertically downward direction, which relations are correct?

Select all that apply

G1 Physics · Accepted Answer

The rise from the bottom is R(1−cosθ), giving A. Taking inward radial direction toward the centre gives T−mg cosθ=mv²/R, hence T=mv²/R+mg cosθ. Tension is perpendicular to instantaneous displacement and does zero work.