A man is running along a road with speed u. On his chest there is a paper of mass m and area S. There is a wind blowing against the man at speed V. Density of air is `rho`. Assume that the air molecules after striking the paper come to rest relative to the man. Find the minimum coefficient of friction between the paper and the chest so that the paper does not fall ?

Answer

`mu_(min)=(mg)/(rhoS(V+u)^(2))`