中文辅助说明
拖动蓝色施力点和橙色箭头改变方向；力与杆长保持固定。学习模式用直角三角形突出斜边、对边和直角，对照 F⊥ = F sin θ 与 d⊥ = r sin θ。练习以一般角度为主，每轮十题。图面可拖动空白处平移、滚轮缩放，也可用加减与复位按钮。
Find r, then compare it with F
Blue: r · Orange: F Drag the background to pan · Scroll to zoom
Drag the blue point or orange arrow, or use the sliders.
Angle between vectors θ
Moment magnitude |τ|
Direction of rotation
The rigid rod turns about the fixed pivot O. Arrow lengths are illustrative and use separate scales.