物理题Hanging Chain

A thin flexible gold chain of uniform linear density has a mass of 12.7 g. It hangs between two 30.0 cm long vertical sticks (vertical axes) which are a distance of 30.0 cm apart horizontally (x-axis), as shown in the figure below which is drawn to scale.

Evaluate the magnitude of the force on the left hand pole.

一个重12,7克的链子挂在30厘米的并相聚30里面的两根柱子上，问左侧极点受多少力