But for other materials, the kinetic friction can be lower than static friction.

没有系数小于系数的情况没有系数小于系数的情况。

Kinetic Friction and Static Friction? What's the difference?

？有什么区别？

Kinetic friction will also often generate heat or sound or both.

它还可以抵抗 热量，声音，或两者兼而有之。

Also, for two surfaces, the coefficient of static friction is almost  always more than the coefficient of kinetic friction.

此外，对于两个表面，系数几乎总是大于系数。

Like the time we rolled a bunch of stuff down a ramp, and pretended that there was no kinetic friction.

就像我们推出一些东西的时候 斜坡并声称没有。

When the two surfaces  are sliding relative to one another, the friction is kinetic and the equation  works out to be the force of kinetic friction equals the coefficient of kinetic  friction times the force normal.

当两个表面相对滑时，是的， 其公式为力等于系数乘以法向力。