“摩擦力”的英语？

活塞上涂了一层石墨以减小摩擦力。The pistons are graphite-coated to reduce friction.润滑油能减小摩擦力.Oil can reduce friction.这种自行车的设计成功地减少了风的阻力和摩擦力。The design of the bicycle has managed to reduce the effects of wind resistance and drag....