Putnam 1946 B6
Source: Putnam 1946
March 13, 2022
Putnamvector
Problem Statement
A particle moves on a circle with center , starting from rest at a point and coming to rest again at a point , without coming to rest at any intermediate point. Prove that the acceleration vector of the particle does not vanish at any point between and and that, at some point between and , the acceleration vector points in along the radius