树枝上的小鸟——趣说刚体平衡

RIGID EQUILIBRIUM AS EXEMPLIFIED BY BIRDS STANDING ON A BRANCH

为了提高理论力学课堂的趣味性,本文以树枝上小鸟作为刚体平衡的例子,应用力的平行四边形法则、力的可传性、三力平衡汇交定理等基本原理分析了树枝上小鸟的双腿受力,以及啄木鸟尾巴在保持身体平衡中的作用,并讨论了小鸟不同姿态对其受力的影响,期望达到提高学习兴趣、寓教于乐、改善教学效果的目的。

To enhance the students’interest for studying Theoretical Mechanics,two teaching cases of static equilibrium are designed in this paper,as the static analysis for birds standing on a branch.Some knowledge points,such as the parallelogram of force,the transmissibility of force,the three-force balance intersecting principle and the conditions of rigid body equilibrium,are used to analyze the forces on the bird’legs on a branch;and the function of the woodpecker tail when it pecked the worm.It is a very enjoyable and educational experience for the students,and can raise students’interest in learning and improve teaching results.