The general inference and demonstration of the equilibrium problem of particle system are carried on, the full and necessary conditions are given while the constraint is ideal, linear and scleronomic.

本文就质点系平衡问题进行了一般性的推证，给出了当约束是理想、线性定常约束时的质点系平衡的充要条件。

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As Haddin and Clarke displayed their full range of strokes in ideal batting conditions he must have had cause to regret that option as Dale Steyn and Makhaya Ntini were thrashed all around the Wanderers.

BBC: Australia end series on high note