A simple seconds pendulum is constructed out of a very thin string of thermal coefficient of linear expansion `alpha = 20 xx 10^(-4)//^(@)C` and a heavy particle attached to one end. The free end of the string is suspended from the ceiling of an elevator at rest. the pendulum keeps correct time at `0^(@)C`. when the temperature rises to `50^(@)C`, the elevator operator of mass `60 kg` being a student of Physics accelerates the elevator vertically, to have the pendulum correct time. the apparent weight of the operator when the pendulum keeps correct time at `50^(@)C` is `("Take " g = 10m//s^(2)`)

Answer

66