The principle of the wind trolley is mainly based on aerodynamics and mechanical transmission principles. Wind cars usually consist of body, sails, wheels and other components. When the wind blows against the sail, the sail is pushed by the wind, creating forward momentum. This power is converted into the rotational force of the wheels through mechanical transmission devices, such as connecting rods, gears, etc. The rotation of the wheels drives the car forward on the ground.

风力小车的行驶速度和方向受风力大小和方向的影响。风力越大，小车行驶的速度就越快；风的方向则决定了小车的行驶方向。因此，在制作风力小车时，需要精心设计和调整风帆的角度和大小，以最大化利用风力，实现小车的稳定行驶。

风力小车不仅展示了风能转化为机械能的原理，也体现了人类对自然能源的巧妙利用。通过制作和玩耍风力小车，我们可以更直观地了解风力的作用和应用，感受科学的魅力。