- A light elastic string has natural length 8 m and modulus of elasticity 80 N .
The ends of the string are attached to fixed points \(P\) and \(Q\) which are on the same horizontal level and 12 m apart. A particle is attached to the mid-point of the string and hangs in equilibrium at a point 4.5 m below \(P Q\).
- Calculate the weight of the particle.
- Calculate the elastic energy in the string when the particle is in this position.