Motor vehicles need energy to accelerate (overcome inertia), to push the air out of their way (aerodynamic drag), and to overcome the friction from tires, wheels and axles (rolling resistance).

• 带发动机的车辆需要能量进行加速(克服惯性阻力)，推开路上的空气(空气动力学拖曳力)，并克服轮胎、车轮和车轴的摩擦力(滚动阻力)。