抛射体最佳抛投角演示仪

The Demo Instrument for the Optimal Throwing Angle of a Projectile

本研究目的：描述、演示体育运动中抛体运动─抛点高于落点（推铅球等）。抛点低于落点（投篮等）、抛点落点同高的最佳抛投角变化特点规律及演示仪的原理和结构。本演示仪利用体育运动与机械运动共同的力学性质，以流体压强差为动力，通过连续流体喷射点角度变化，观察不同抛落位置相应的最大射程和最佳抛射角。教学实践证明该演示仪能将体育运动中难以观察的快速抛投器械运动的力学原理、特点、规律很好地显示出来，直观效果好，设计有创新性，其力学原理学生可直观接受。

The aim of the research is to describe and to show the alternative relationship, the speciality and the law of a projectile's movement──the throwing point is higher than the falling point (as in shot-puttlng), the throwing point is lower than the falling point (as in basketball shooting), and the throwing point is as high as the falling point. It also shows the construction and the principle of the demo instrument.According to the common mechanical property of mechanical movement and athletic sports, motivated by the difference of hydro-pressure, the demo instrument can observe the farthest distance and the Optimal throwing angle θ_m, corresponding to the different positions of throwing points and falling points, through the angle changes of spurt point of continuous liquid.The demo instrument can well demonstrate the dynanism characteristics and the law of the throwing device's movement, which is usually hard to be observed in teaching practice. It is an innovative devise and has a goods audio-visual effect.Students can accept its mechanical principles directly.