A uniform heavy chain of length L lies on a horizontal table, coefficient of friction μ=0.25. What maximum fraction of its length can overhang the edge in static equilibrium?
Options

Question

A uniform heavy chain of length L lies on a horizontal table, coefficient of friction μ=0.25. What maximum fraction of its length can overhang the edge in static equilibrium?

G1 Physics · Accepted Answer

Let overhang x and linear mass density λ. Hanging weight λxg is balanced by maximum friction μλ(L−x)g on the tabletop. Set x=μ(L−x), giving x/L=μ/(1+μ)=0.25/1.25=1/5=20%. Answer: A.