Question

A meter stick has a mass of 0.24 kg and balances at its center. When a small chain is suspended from one end, the balance point moves 27.0 cm toward the end with the chain. Determine the mass of the chain.

Answer 1

Given

meter stick of lenght l = 1 m

mass M = 0.24 kg

let the mass of the chain be m

if the chain is at one end(left) , the balance point moves to 0.27 m, towards the chain end

the moments (torque) with respect to new balance point are

   m*g0.27 -M*g(0.23) = 0

   m*g(0.27) = M*g(0.23)

   m = M*g(0.23) /(g(0.27))

   m = M(0.23) /(0.27)
  
   m = 0.24*0.23/0.27 kg

   m = 0.2044 kg
so mass of the chain is m = 0.2044 kg