Question

A belt supports two weights W₁ and W₂ over a pulley as shown in fig If W₁ = 1000N, find the minimum weight W₂ to keep W₁ in equilibrium. Assume that the pulley is locked and µ = 0.25.

Answer 1

Let the tensions in the belt be T₁ and T₂ as shown, since the weight W₂ just checks the tendency of weight W₁ to move down, tension on the side of W₁ is larger. 

That is, T₁>T_2.

Using the relation Ratio of belt tension 

= T₁/T₂ = eµθ

W₁/T₂ = e^(0.25)(Π)

On solving, T₂ = W₂ = 456N.