static friction coefficient

例句：

1. 1.The car is stationary at the traffic lights.
   汽车在红绿灯处静止。
2. 2.The earth's magnetic field is a static force.
   地球的磁场是一种静态力。
3. 3.The temperature on the surface of the Earth is static.
   地球上表面的温度是静态的。